water help no hot water

[jpbroad1970]

hi we have an issue with our heating and water system . new flow switch and new pump , system bled , all done by a professional but still no hot water or heating. when the plumber left yesterday we had boiling radiators and some hot water although the heating was switched off. my suspicion is diverter valve but unsure as to why nothing is working again now. boiler tries to kick in but says FD error (flow)

would be really happy for some advice as we have been 4 weeks without hot water no and the Mrs isn't happy.

thanks in advance
John

 

[Burger]

Hi John,

I suggest getting your professional plumber back if he/she has supposedly fixed it?

What boiler is it?

 

[jpbroad1970]

i tried that lol but they arent answering now or even rang me back. daft as they are local and installed the boiler 4 years ago. looks like weve had a pump for no reason too grrrr

 

[Burger]

looks like weve had a pump for no reason too grrrr

- maybe they aren’t into boiler repairs?

What boiler is it?

 

[jpbroad1970]

its a logic plus 18 i think from memory as im at work. with hot water cylinder and tank in loft 3 way honeywell motorised valve

 

[Aire]

Is it an ideal boiler? Which one? It's or a only 4 years old I'd expect it to still be under warranty. If not then perhaps give the manufacturer a call and ask about a fixed price repair.

 

[jpbroad1970]

it is an ideal so it must be 5 years as its just out of warranty, i dont think its the boiler as it was working again yesterday but couldnt switch heating side off without turning radiators off.

 

[Burger]

it is an ideal so it must be 5 years as its just out of warranty, i dont think its the boiler as it was working again yesterday but couldnt switch heating side off without turning radiators off.

Sounds like it could be your 3 port valve or even the programmer. Start with everything cold, put a call/demand for hot water and feel your pipe leading to the cylinder on 3 port (should be Port B). Now it probably won’t get hot as you said you don’t have hot water, then feel Port A side (heating) if this is hot then it’s more than likely 3 port being the issue.

 

[Aire]

it is an ideal so it must be 5 years as its just out of warranty, i dont think its the boiler as it was working again yesterday but couldnt switch heating side off without turning radiators off.

Yeah I was typing my reply before you mentioned it was a heat only boiler. Why couldn't you switch the heating off? If the system was running when there was no demand, the first place I'd be looking is at the 3 port valve, unless there's a wiring fault, this is the only valve that can overide the controls and fire the boiler up

 

[Burger]

Also if you diagnose this to be the fault, either employ a different plumber or maybe even stat wher you are located and perhaps one of the fine chaps on here could help?

 

[jpbroad1970]

Yeah I was typing my reply before you mentioned it was a heat only boiler. Why couldn't you switch the heating off? If the system was running when there was no demand, the first place I'd be looking is at the 3 port valve, unless there's a wiring fault, this is the only valve that can overide the controls and fire the boiler up

all the controls were off for heating but it was still heating all the radiators. im going to have a quick look this afternoon see if i can see anything obvious especially on the 3 way valve. electrics out of my remit on controls really but these havent been touched other than the new pump being wired.

 

[jpbroad1970]

Also if you diagnose this to be the fault, either employ a different plumber or maybe even stat wher you are located and perhaps one of the fine chaps on here could help?

i think that may be the case , im in rushden northants

 

[jpbroad1970]

Ok here's where I'm at. Took the front off diverter valve and I can move the shaft left and right. Left motor off to see what happens with flow when I turn the valve. Nothing to the left and nothing to the right but in the middle heating and hot water.

 

[jpbroad1970]

Another follow up, water is flowing without the diverter head on and me set the pin to the middle, turned all the rads off to stop the flow around them. It will do temporarily until someone can come round or I'm sure it's diverter valve, thinking I need a complete valve assembly as I'm thinking it's breaking down a bit inside. But I'm not too confident draining the system.

 

[Burger]

Another follow up, water is flowing without the diverter head on and me set the pin to the middle, turned all the rads off to stop the flow around them. It will do temporarily until someone can come round or I'm sure it's diverter valve, thinking I need a complete valve assembly as I'm thinking it's breaking down a bit inside. But I'm not too confident draining the system.

It could be, but you’d be better someone else take a look. I’m surprised no one on here has been in touch.

 

[jpbroad1970]

I'm hoping, it's still working without the head on valve but only in middle.

Hopefully someone get in touch

 

[RoryD]

Hopefully the diverter has been put on the correct way arround and wiring to the Clock is ok? With a 3 port Valve the cylinder stat can actually affect how it operates. I've had it where the heating stays on and only water. I'd be having all those checked

 

[jpbroad1970]

Hopefully the diverter has been put on the correct way arround and wiring to the Clock is ok? With a 3 port Valve the cylinder stat can actually affect how it operates. I've had it where the heating stays on and only water. I'd be having all those checked

Thanks
The wiring hasn't been touched, it's original valve and clock so my assumption is it's mechanical but I'm no heating engineer.

Good news is it's kicking in and out this morning still with top on motorised valve. I will clean the magna clean out again today and see how we go.

 

[Brambles]

If you are are in Northants, I have someone in Finedon next week who could look at it for you if you are still having problems. Drop me a line if that suits. [email protected]

 

[jpbroad1970]

Thanks very much, going to try the original plumber as it's his responsibility really but if I have no joy I will message you.

Could anyone please confirm the drain down method, in my mind it's lock off the tank in the loft then turn on hot taps to drain down tank , when that's drained drain the hot water loop from the drain tap at boiler then hey presto should be clear to take off diverter valve.

 

[Aire]

Thanks very much, going to try the original plumber as it's his responsibility really but if I have no joy I will message you.

Could anyone please confirm the drain down method, in my mind it's lock off the tank in the loft then turn on hot taps to drain down tank , when that's drained drain the hot water loop from the drain tap at boiler then hey presto should be clear to take off diverter valve.

No need to drain hot water, your hot water and heating water are seperateted you'll have two tanks in the loft, close off the small one. Turn off power supply to boiler, open drain valve, wait for water to stop, then open bleeds on upstairs rads, wait for water to stop, then open bleeds on downstairs rads. Don't forget to add inhibitor back in the system when filling back up. Also check the condition of the water when you drain down. If it's mucky it might give a clue as to why your system is having issues

 

[jpbroad1970]

No need to drain hot water, your hot water and heating water are seperateted you'll have two tanks in the loft, close off the small one. Turn off power supply to boiler, open drain valve, wait for water to stop, then open bleeds on upstairs rads, wait for water to stop, then open bleeds on downstairs rads. Don't forget to add inhibitor back in the system when filling back up. Also check the condition of the water when you drain down. If it's mucky it might give a clue as to why your system is having issues

Thanks very much, got me head confused on the water heating loop lol. I'm happy doing that , I have drained the upstairs rads before do I have to drain the downstairs rads too?

 

[Aire]

If your 3 way valve is above your downstairs rads then no you won't need to drain them.

 

[jpbroad1970]

If your 3 way valve is above your downstairs rads then no you won't need to drain them.

3 way valve is on is in airing cupboard upstairs, boiler is downstairs we only have 2 floors.

 

[jpbroad1970]

Hi, the saga continues, plumber came back and put new diverter valve on, we have come back off holiday and no hot water, pump works diverter valve works , as said before new flow sensor fitted too, only thing I noticed when I cleaned magna clean is metal fragments attached , will try to add a picture. We are going to get a different plumber, could I be right in thinking all the pipes could be caked up in the fragments. We are at a loss now as the best route to follow as if my understanding is correct it's really just a simple flow circuit.

 

[Burger]

What’s your cylinder thermostat set to?

 

[jpbroad1970]

What’s your cylinder thermostat set to?

That's set 70 degrees at the moment but the hot water tank is stone cold

Thanks

 

[Burger]

That's set 70 degrees at the moment but the hot water tank is stone cold

Thanks

And have you checked your 3 port again? If that's coming out of your filter, could be blocking your 3 port 😱

 

[jpbroad1970]

And have you checked your 3 port again? If that's coming out of your filter, could be blocking your 3 port 😱

I tried the new 3 port on manual setting and that didn't help, also tried heating and that's not functioning although you can hear the valve motor move. I know is difficult to diagnose on the internet but it's doing is in. If I knew how I could flush it through I would try myself but other than that it's midweek untill we can get a new plumber out. There can't be much else in the system can there. Again I'm guessing but there must be a blockage somewhere. You can hear the water start to flow and you can feel it throughout the pipes to tank but I suppose that could be pump vibration.

 

[Burger]

Ok so you've tried 3 port in manual, are any pipes getting hot? Does the boiler fire up? Can you get hot water from immersion?

 

[jpbroad1970]

Nothing is getting hot , boiler won't fire just keeps coming up flow fault. I don't know if the emersion is still connected as I can see wires or where a heating element would be.

 

[jpbroad1970]

We don't have an Immersion heater, looks like it's been took out but the switch is still there.

 

[Burger]

Did your plumber have to drain anything to change 3 port? If it’s a flow fault it could be the pump.

 

[jpbroad1970]

I presume I can wire in a Immersion heater, I'm just trying to find the length I can use. Attached image is my tank info.

 

[jpbroad1970]

Did your plumber have to drain anything to change 3 port? If it’s a flow fault it could be the pump.

We have new pump , new boiler flow switch, new 3 way valve and no luck lol

 

[Burger]

I presume I can wire in a Immersion heater, I'm just trying to find the length I can use. Attached image is my tank info.

Yes you can, you’d need a 27” one. Are you ok with electrics?

 

[Burger]

We have new pump , new boiler flow switch, new 3 way valve and no luck lol

Looking at the shiote in the filter, could be stopping it. Can you take a photo of your pump (if it’s near cylinder) and 3 port layout? Just to maybe get a different perspective.

 

[jpbroad1970]

Yes you can, you’d need a 27” one. Are you ok with electrics?

Yeah I'm good with electrics, just something for temp and emergency measures like this.

 

[jpbroad1970]

Looking at the shiote in the filter, could be stopping it. Can you take a photo of your pump (if it’s near cylinder) and 3 port layout? Just to maybe get a different perspective.

Best I can get I'm afraid no David bailey

 

[Burger]

Hard to tell from that photo, but I’m unsure if that first valve on the pump is fully open? Check both are fully open (anti-clockwise). Also check your boiler thermostat is turned up.

 

[jpbroad1970]

It was all working on pump speed 2 then only on 3 now nothing . All taps are open as should be so lord only knows.

 

[Aire]

Are you getting no flow on heating and hot water or just when your calling for hot water?

 

[jpbroad1970]

Are you getting no flow on heating and hot water or just when your calling for hot water?

On both , when it was first so called repaired it all worked on pump speed 2 , but then struggled so had to be moved to 3, my thinking is it's a blockage moving around but I'm doing a lot of thinking over it all probably too much lol.

 

[Aire]

On both , when it was first so called repaired it all worked on pump speed 2 , but then struggled so had to be moved to 3, my thinking is it's a blockage moving around but I'm doing a lot of thinking over it all probably too much lol.

It could easily be an airlock after the repair. The plumber most likely drained down to some degree to change the valve so an air lock would not be uncommon. Try cycling your hot water on and off for a few minutes. Using the programmer turn the hot water on, for 10 - 20 seconds, off for 10 - 20 seconds and do this for a few minutes. You should be able to hear the water move and possible hear bubbles in the system. Other than that it could be a blockage or even a blocked cold feed/dried up f&e tank.

 

[Burger]

Did you check the boiler thermostat? And as per @Craig Watson check the f&e tank has water in it. Are there any valves where the pipes connect to the boiler?

 

[jpbroad1970]

Did you check the boiler thermostat? And as per @Craig Watson check the f&e tank has water in it. Are there any valves where the pipes connect to the boiler?

F&e tank ?

Boiler thermostat ok too

 

[Burger]

F&e tank ?

Boiler thermostat ok too

Feed and expansion (sometimes referred to as header tank), or is it a sealed system? In which case do you have correct pressure?

 

[Harvest Fields]

I am loving the position of the Adey filter.

 

[jpbroad1970]

Feed and expansion (sometimes referred to as header tank), or is it a sealed system? In which case do you have correct pressure?

I'll check f and e tank , I have no pressure gauges on boiler or anywhere else for that matter so I presume it's not a sealed system.

 

[jpbroad1970]

I have header tank and cold water tank, both full.

Also now can't get the cap off to fit Immersion heater. Omfg

 

[Harvest Fields]

I have header tank and cold water tank, both full.

Also now can't get the cap off to fit Immersion heater. Omfg

What tool are you using to try and remove it?

 

[Jones82]

Sounds like air in the system, try bleeding all radiators and any manual / automatic vent points. If no air comes out I'm afraid you'll have to hire another plumber or get the first one back, I hope you haven't paid him!

I would never leave a customer like this

 

[jpbroad1970]

What tool are you using to try and remove it?

32mm socket and wrench as that fits the blanking cap a treat

 

[jpbroad1970]

Sounds like air in the system, try bleeding all radiators and any manual / automatic vent points. If no air comes out I'm afraid you'll have to hire another plumber or get the first one back, I hope you haven't paid him!

I would never leave a customer like this

We have paid him as it was working. Albeit was only £240 but it's the time frame.

 

[Aire]

I have header tank and cold water tank, both full.

Also now can't get the cap off to fit Immersion heater. Omfg

The smaller of the 2 tanks, what was the condition of the water like, did you try pushing a screwdriver or something into the tank outlet to make sure it was clear?

 

[jpbroad1970]

The water was,is dirty. It was a bit caked up but free flowing now, rads have bled and you can tell when the pump kicks in as it increases the pressure of water coming out the rad.

 

[Aire]

What do you mean by was caked up but free flowing now?

 

[jpbroad1970]

What do you mean by was caked up but free flowing now?

It had some crusty bits just inside the outlet

 

[jpbroad1970]

I have given up , plumber booked ran out of ideas and patience.

 

[jpbroad1970]

Thanks everyone for your input, I'll post up results when mended.

 

[jpbroad1970]

Ok am I doing something wrong, this is the tap the plumber drained the water out of the system with above the boiler. In my little mind I thought if I opened that valve/tap water should come out, am I wrong do I have to open anything else. I don't want to completely drain everything down just view the water or make sure it's making it to the boiler and it's not just air pushing around.

 

[Burger]

Ok am I doing something wrong, this is the tap the plumber drained the water out of the system with above the boiler. In my little mind I thought if I opened that valve/tap water should come out, am I wrong do I have to open anything else. I don't want to completely drain everything down just view the water or make sure it's making it to the boiler and it's not just air pushing around.

Yes that’s the drain cock and is used for draining purposes.

 

[jpbroad1970]

So I should have water come out of that?

 

[Aire]

So I should have water come out of that?

Water will come out so long as the washer isn't stuck or the valve blocked. If the plumber recently used it then it should be fine. What I would do is attach a hose, open the valve and then go in the loft to check that the water level in the tank drops and refills. This will prove if the cold feed is blocked or not.

 

[jpbroad1970]

Water will come out so long as the washer isn't stuck or the valve blocked. If the plumber recently used it then it should be fine. What I would do is attach a hose, open the valve and then go in the loft to check that the water level in the tank drops and refills. This will prove if the cold feed is blocked or not.

Nothing comes out when I undo the square bit, do I have to push or press anything, it opens very easily but not even a drip out of it when square bit fully open.

 

[Aire]

Nothing comes out when I undo the square bit, do I have to push or press anything, it opens very easily but not even a drip out of it when square bit fully open.

If it was me, I'd slightly unscrew the circular nut that the square nut passes through, don't take it all out but it will allow you open the drain valve further, this can sometimes free off the washer in the valve. Be warned though, if the washer is knackered you could find the valve won't re seal. Personally I'd wait till tomorrow till shops are open to get a replacement if needed.

 

[Burger]

If it was me, I'd slightly unscrew the circular nut that the square nut passes through, don't take it all out but it will allow you open the drain valve further, this can sometimes free off the washer in the valve. Be warned though, if the washer is knackered you could find the valve won't re seal. Personally I'd wait till tomorrow till shops are open to get a replacement if needed.

I Agree with Craig, best wait til tomorrow 🙂

 

[jpbroad1970]

I've given up properly now.

That lock ring thing was quite loose.

My partner said she saw the the plumber draining water out there with hose attached with clear water running through, again in my head the colour of water in header tank how can it be running clear.

 

[jpbroad1970]

I think it's beyond my knowledge understanding. I can see how it all works but I'm not a plumber and I think it's best left to the professionals, just not the same one we had before.

Thanks again for all the advice.

 

[Burger]

Thanks again for all the advice.

No worries, it’s why we’re here. I hope you get sorted, can you let us know how you get on? 😉

 

[jpbroad1970]

No worries, it’s why we’re here. I hope you get sorted, can you let us know how you get on? 😉

Yeah I will post the results, they should come tomorrow or Tuesday.

 

[jpbroad1970]

Well another 5 hours with a different plumber and guess what, no hot water or heating. I'm at work but the Mrs has said they have replaced a load of pipework in the airing cupboard and got some sludgy water out. But it's still coming up flow error. Going to have to come back another day, dread to think on cost of this little lot. Sad times.

 

[Aire]

Well another 5 hours with a different plumber and guess what, no hot water or heating. I'm at work but the Mrs has said they have replaced a load of pipework in the airing cupboard and got some sludgy water out. But it's still coming up flow error. Going to have to come back another day, dread to think on cost of this little lot. Sad times.

When you get home take a pic of the new pipe work, just to keep us updated.

 

[jpbroad1970]

Will do no problems. They were on about new radiators and all sorts Mrs is leaving piles of brown poo everywhere

 

[Aire]

Will do no problems. They were on about new radiators and all sorts Mrs is leaving piles of brown poo everywhere

Why New radiators? If they're sludged up just take them off, give them a flush with hose pipe outside and they'll be fine.

 

[Aire]

Did you ever contact @Brambles about the work? You initially told him you would give your original plumber another chance first but obviously he's been sacked off now.

 

[jpbroad1970]

I haven't yet no, we got the other plumber to fit the 3 way valve then paid him as it was ok for a couple of days then we went away . The Mrs then called the people that service our boiler yearly and to be fair they turned up as promised, even put a job off to do ours. If it's just a case of flushing the rads with a hose pipe that's something I can do easy enough, had rads off before and fitted new ones so sure I can manage that.

 

[Harvest Fields]

If it is sludge will a powerflush not help?

 

[jpbroad1970]

I think that's what it's looking like. They drained water off as per pic.no real metal bits just sludge and mucky water. Their opinion and that's all it is at the moment is as soon as the pump starts to drawer water it's drawing sludge slowing everything down to a stop.

 

[jpbroad1970]

Tall glass what they fetched off

Small glass what I've just drained out of tap off the top of the boiler pipe

 

[spanner]

When it's in hot water on from programme, with cylinder start set to 55-60 boiler should fire. Probably heads gone on actuator or fault with motor or three port wiring

 

[jpbroad1970]

When you get home take a pic of the new pipe work, just to keep us updated.

That's new pipes, not as many as I thought but new none the less.

 

[jpbroad1970]

When it's in hot water on from programme, with cylinder start set to 55-60 boiler should fire. Probably heads gone on actuator or fault with motor or three port wiring

It's had new pump, new actuator if that's diverter valve.

 

[jpbroad1970]

A bit more info, when the new Plumber was doing his stuff the water he got to run clear and the hot water started to heat up, he then tried the heating side and that screwed the whole system.water went all crap again and boiler wouldn't fire.

 

[Aire]

That's new pipes, not as many as I thought but new none the less.

They've replaced the cold feed, it's a typical place for the system to block up there. Obviously there's no way of knowing whether it was blocked or not though. I personally wouldn't have installed a iso valve either, I'd have gone with a full bore valve and removed the handle so it can't accidently be turned off.

 

[Aire]

A bit more info, when the new Plumber was doing his stuff the water he got to run clear and the hot water started to heat up, he then tried the heating side and that screwed the whole system.water went all crap again and boiler wouldn't fire.

Sounds like a good power flush should see you right.

 

[Millsy 82]

To me it looks like the pumps are fine it's the fact that the flow and return are joined together that gets me.

But in all honesty I cant really make every thing out as it hurts my eyes. RIP it out and do it again.

 

[Aire]

To me it looks like the pumps are fine it's the fact that the flow and return are joined together that gets me.

But in all honesty I cant really make every thing out as it hurts my eyes. RIP it out and do it again.

It's not required but I thought that was a bypass and that the gate valve would only be partially open.

 

[jpbroad1970]

Thanks again guys my head hurts no and the Mrs is proper Soded off.

 

[Burger]

I’d think about getting in touch with @Brambles, very knowledgeable (more than me, which isn’t hard 😀). Didn’t know he was near to you? Might actually get it sorted.

 

[Millsy 82]

It's not required but I thought that was a bypass and that the gate valve would only be partially open.

I didnt even see a gate valve 😱

 

[John.g]

Thanks again guys my head hurts no and the Mrs is proper ****ed off.

If that pump now actually running and on speed 3 then it should be showing a power output of > 35W.

 

[jpbroad1970]

The pump just switches off when the flow message comes up but yes it displays between 29 and 34 watt when running.

 

[John.g]

The pump just switches off when the flow message comes up but yes it displays between 29 and 34 watt when running.

OK then, if that is a 6M pump and running on fixed speed 3 @ 30W then it is only circulating ~ 0.2 m3/hr or 3.3 LPM, just turn the rotary knob fully clockwise and then back it off a little, when it starts up adjust it to read 4M (flashing), it will then change to display the power, if, in fact the flow rate is only ~ 3 LPM then it will only read 15/18w, the higher the better, to give any meaningful flow at this setting it should read ~ 25W which is ~ 13/15 LPM.

 

[Brambles]

JP

I would be wary of trying to fix this by making ad hoc modifications ( new bits of pipe and valves et al ) and then trying to run the system. You run the possible risk of either making the problem worse or possibly causing expensive damage to the boiler.

Isolate the heating system other than one radiator (preferably the one closest to the boiler ) and then systematically work through the boiler + single rad hydraulic system. At the same time check and test the individual controls against the logic diagram. Also fit a quality magnetic filter on the return to the boiler.

Once you are satisfied that you have a clear hydraulic path on your mini system - configure the pump to run with the boiler off and satisfy yourself you have a good clean flow path.

Thereafter and only when you have a clear hydraulic flow path, get the boiler operational at minimum rate and stable before you systematically look at the rest of the system.

At the end of the day, you have a fairly straightforward system to analyse, approach it in a logical step by step fashion - and make sure that you have not had anyone in to work in this problem who has changed the flow paths.

Always have in mind that you may have more than one problem with the system - hence the need to be systematic, patient and don’t jump to conclusions (sludge is an issue, but in my experience, a serious sludge problem = no flow, not erratic flow which are (to my mind) the symptoms you are describing ).



A suggestion - get the new iso valve by the pump removed - it is not full bore so is restricting flow - it may seem churlish, but the last thing you need at the moment is anything that disrupts or distorts the hydraulic flow

Hope this helps

 

[jpbroad1970]

JP

I would be wary of trying to fix this by making ad hoc modifications ( new bits of pipe and valves et al ) and then trying to run the system. You run the possible risk of either making the problem worse or possibly causing expensive damage to the boiler.

Isolate the heating system other than one radiator (preferably the one closest to the boiler ) and then systematically work through the boiler + single rad hydraulic system. At the same time check and test the individual controls against the logic diagram. Also fit a quality magnetic filter on the return to the boiler.

Once you are satisfied that you have a clear hydraulic path on your mini system - configure the pump to run with the boiler off and satisfy yourself you have a good clean flow path.

Thereafter and only when you have a clear hydraulic flow path, get the boiler operational at minimum rate and stable before you systematically look at the rest of the system.

At the end of the day, you have a fairly straightforward system to analyse, approach it in a logical step by step fashion - and make sure that you have not had anyone in to work in this problem who has changed the flow paths.

Always have in mind that you may have more than one problem with the system - hence the need to be systematic, patient and don’t jump to conclusions (sludge is an issue, but in my experience, a serious sludge problem = no flow, not erratic flow which are (to my mind) the symptoms you are describing ).



A suggestion - get the new iso valve by the pump removed - it is not full bore so is restricting flow - it may seem churlish, but the last thing you need at the moment is anything that disrupts or distorts the hydraulic flow

Hope this helps

thanks for that, it is getting a bit to much for me really I can only do very basic stuff. we just need someone to fix it lol , its been nearly 5 weeks now and I have no more hair left to pull out. I have a logical mind but I just cant seen to get my head around this. if we could just get hot water that would be ok for now until the rest can be fixed but its just not going right. in my head yet again ive got set the timer so its just HW which should close the rads off? drain the water out from the tap above boiler until it runs clear and see if the boiler then kicks back in or is that too simple, if that worked for a couple of days or so I could start opening one rad at a time. im getting to a point where im over thinking and clutching at straws I think.

 

[Brambles]

JP

I have not seen the system - but it is not complex. At a basic level there is something that is severely restricting flow - I doubt that that is just sludge ( but I am possibly wrong).

From a heat perspective, the issue you appear to have is either at or before the three position valve and the heat exchanger, where the pipework is of a reasonable diameter - but the heat exchanger obviously is not.

I would not keep on trying to fire the boiler until I was satisfied that I had a clear hydraulic path through the boiler - if you do and the overheat sensors fail ( unlikely, but if they are being tested repeatedly!) you could make the current problem worse.

On issues where a number of people have tried to fix it, you sometimes find that with the best will in the world they have changed something that has compounded the problem.

It is unlikely that the people you have had to look at the system are novices, but I think it is likely that you have at least two concurrent problems.

With respect to the people who have “serviced” your boiler - they have not in my view done a proper job - the quality of your system water has not got into that state in a year.

It is generally easier ( in my experience ) to get a system operational from the central heating circuit rather than the hot water side ( it eliminates any potential issues that may be within the tank pipework)

 

[jpbroad1970]

I haven't changed anything its all been done by "qualified " plumbers.

the boiler was serviced in February if I remember correctly.

 

[John.g]

I haven't changed anything its all been done by "qualified " plumbers.

the boiler was serviced in February if I remember correctly.

Its probably most unlikely but you can easily check that the circ pump is pumping in the right direction by checking the arrow on the pump body, also if you are thinking of doing a few things yourself, if you can run the pump with a separate (elec) supply with boiler powered off and then open that three way valve manually to its various settings you can then play around with venting rads etc and see if that pump power increases (speed 3), it should increase to ~ 38/40 W and you will then know that you are getting a decent flow before firing up the boiler again.
If a decent flow rate cannot be achieved then possibly the boiler Hx is fouled.

 

[jpbroad1970]

forgot to mention the pump initially drawers 28w on start up then drops to 27 on speed 2 is 11w