Baffled by central heating with a mind of its own......ready to give up!!

[tamz]

Start with swapping the pump head.
Filter would be a permanent problem and air locks or sludge doesn't float about a system in the manner you describe.
Best if you can get someone who knows what they are doing on the job to see what is actually happening.
Stan (safegasinstall) on here is in your area and knows his stuff but hasn't been on for a wee while. PM him.

 

[jase158]

I am in Aylesbury, I usually book in for powerflush and survey on the day, If i don't think it will need it then I quote on the day then we quote for what it does need.

Does sound like you need to take the rads off and flush out outside, only thing that has been forgotten is that you open the valves a little into a bucket to ensure you are getting flow to each side.

Make sure boiler is off and system is pressurised!! If it is a pressurised system, you could connect hose to radiator valve and flush it through, using the filling loop, so pipework gets a clean as well as rads!!

 

[Ollieg]

You have a heatline viso, which is a combi as far as i know.
If you had a sludge problem the dhw heat exchanger would have been blocked long ago (no hot water). I dont think you have a sludge problem.
Fundamental pipework problem is where I think the issue is.

 

[diamondgas]

boiler fires up and feed pipe gets red hot, can sometimes get warmth in the return but takes a bit of fiddling with the system.

is the nut covering the filter about 30mm diameter? If so i think ive located it...will need some grips to undo as its more than finger tight....will try carefully tomorrow....there is a blue tap to stop flow just before it....should i turn off boiler and this flow via blue tap prior to removing nut....i imagine i need to?
thanks

You have to remove the pressure from the system before you remove the nut. Yes it's a 'blanking cap nut' If you can get the valve turned off then it doesn't hard to do so, likewise with the flow valve opposite side! They do seize however so don't force them too much!

Have a bucket ready to catch any residual water once you've taken the pressure off/drained down.... If you're at all not sure get someone in to do it!!

Feed pipe red hot and return warm is definitely restricted flow. If the hot water heats okay then you can rule out the pump 🙂

 

[JoseGaf]

Well i found time to get a couple of rads off to clean out......first radiator which has never worked had lots of black water inside....checked the feed and return taps had pressure and they did. Then took off bathroom rad and towel rail which are closest to the boiler and are the rads that i can normally get working.....again these were black inside. Plan tomorrow to get the final 2 downstairs rads cleaned out......1 which has never really worked but i managed to get hot the other day for a while for the first time....the other which used to work last winter.
my plan is to get all of the remaining rads done next wknd then stick some de-sludge solution in......then flush through the following day......hopefully this will all help.....im not running the central heating again until ive cleaned all the rads

 

[Ermintrude]

Leave sludge remover for a week and use heavily

 

[JoseGaf]

Leave sludge remover for a week and use heavily

Ta, any recommendations on what sludge remover to use please?

 

[kay-jay]

Ta, any recommendations on what sludge remover to use please?

Fernox or sentinel or magnaclean brand. Dont buy the cheap stuff.

 

[solutions]

Fernox or sentinel or magnaclean brand. Dont buy the cheap stuff.

Why what is the difference?

 

[kay-jay]

Peace of mind [emoji3]

 

[JoseGaf]

Fernox or sentinel or magnaclean brand. Dont buy the cheap stuff.

Thanks for the advice....with get some ordered

Have now cleaned out 3 rads and a towel rail and haven't turned the heating on at all...just used hot water......all the cleaned rads are closed off at feed and returns......however the boiler pressure is slowly dropping (over a course of hours).....I keep topping up the system to make sure we have hot water......I've only had the downstairs rads off and there are no leaks.....there are no noticeable wet patches up above in the ceiling so I'm wondering where the water is going thats causing the pressure drop.....any ideas??

 

[jtsplumbing]

Did you refill the radiators ? if not valves possibly letting by into radiator

 

[JoseGaf]

Did you refill the radiators ? if not valves possibly letting by into radiator

Cheers....refilled rads and pressure leak seems to be sorted

 

[JoseGaf]

Right, all downstairs radiators have been removed and cleaned out, system drained then 1 litre of x400 sentinel added. Boiler then started up, rad returns opened one by one and bled after each got hot....managed to get heat in all of them for the first time....however once all rads opened 2 of the 3 original problem rads reduced their heat to warm at best....i imagine this is either down to the poor pipe set up meaning 6 rads is probably the max the system can take or the sludge remover just needs more time to run.....hope its the latter

 

[goz666]

How far are you opening the lockshield valves, if I was you I would turn each one off and then open up by one turn and no more. You may find that's too much so try half turn. On a lot of systems balancing is probably the most difficult job there is. Any rads with no TRV, close one side down and reopen one turn.

 

[tamz]

Move the L/s 's in ¼ turns when balancing

 

[diamondgas]

6 days and still little progress JoseGaf .... You have patience 🙂

I've found pipes blocked with stones, rubber washers and even loft insulation as well as sludge!! It's a process of elimination when diagnosing where the origin of the fault lies. Radiators aren't the cause, poor heat to them is the result of restricted flow to them. Experience and understanding in boiler and system design is important when diagnosing and resolving your issue I'd say. Chemicals aren't always the solution to poor flow, sometimes you just have to delve deeper.

Could you sketch out your heating layout, pipe sizes to radiators etc? Maybe then better advice can be given? Did you clean out the filter, by-the-way?

 

[Millsy 82]

Right, all downstairs radiators have been removed and cleaned out, system drained then 1 litre of x400 sentinel added. Boiler then started up, rad returns opened one by one and bled after each got hot....managed to get heat in all of them for the first time....however once all rads opened 2 of the 3 original problem rads reduced their heat to warm at best....i imagine this is either down to the poor pipe set up meaning 6 rads is probably the max the system can take or the sludge remover just needs more time to run.....hope its the latter

You are spending all this time and money trying to repair a bodge (6 rads off 15mm pipe will struggle at best) why not just bite the bullet and repipe the system? Is your time worth so little that you are willing to spend most of your free time trying to sort this when a decent installer will sort it within a couple of days max (I would of thought not seeing the house makes it quite difficult to say for certain)

 

[JoseGaf]

You are spending all this time and money trying to repair a bodge (6 rads off 15mm pipe will struggle at best) why not just bite the bullet and repipe the system? Is your time worth so little that you are willing to spend most of your free time trying to sort this when a decent installer will sort it within a couple of days max (I would of thought not seeing the house makes it quite difficult to say for certain)

I've done a bit of research and messaging on this forum plus I've spent £8 on sentinel sludge remover off ebay and £60 on a couple of oil heaters......other than that 3 hours approx to clean out the downstairs rads.....I appreciate it all needs re-piping and probably a new boiler but I just cannot afford it right now, I don't have £3-4k.....I'm pretty pleased with the results I've had thus far thanks to good advice from guys on this thread.....I have heating again which comes on everytime the boiler fires and I have heat in rads that have never had heat in 4 years. Its not a big house and am sure restricting the flows via the returns along with the cleaning and sentinel have helped a lot.
Next steps are to get the upstairs rads off and cleaned over the next few weeks, drain the system then stick some more sentinel in.

 

[JoseGaf]

6 days and still little progress JoseGaf .... You have patience 🙂

I've found pipes blocked with stones, rubber washers and even loft insulation as well as sludge!! It's a process of elimination when diagnosing where the origin of the fault lies. Radiators aren't the cause, poor heat to them is the result of restricted flow to them. Experience and understanding in boiler and system design is important when diagnosing and resolving your issue I'd say. Chemicals aren't always the solution to poor flow, sometimes you just have to delve deeper.

Could you sketch out your heating layout, pipe sizes to radiators etc? Maybe then better advice can be given? Did you clean out the filter, by-the-way?

Hi, I've not cleaned any filters as I'm not sure of what I'm doing. I have found the user manual for my boiler (heatline viso) on line which has all the parts identified but not sure what needs cleaning....any advice most welcome....I'll have a go at sketching the system