Anything I can try before biting the bullet?

[WaterTight]

Drained the top of floor of a CH system to change to rad valves on towel rad with pipe tails to short to freeze.

Wasn't a combi. Didn't peak in loft when quoting as was in rush.

When I arrived and got in loft to tie ball valve arm up I found water was gravity but there was no f+e. I don't do heating and am not gas safe and am pretty cautious with things I don't understand. But when I saw a big red expansion vessel for CH with a filling loop I thought for a while and decided you probably just treat the primary circuit as if it was off a combi i.e drain, work, re-fill via loop with inhibitor, test. I was worried because I don't really understand the ins and outs of how this particular system might work but talked myself into it.

Customer did not know where power switch was for boiler. Wires went into a wall and disappeared. So thought I'd take a punt (probably very stupid) and leave the power on. Heating and hot water turned off at programmer, boiler was not running. I was once told you can get away with this on a combi but shouldn't risk it on a normal boiler.

After doing work, re-pressurised via filling loop to 1.5bar while cold and bled rads. Turned on heating. Everything got hot, no leaks. Job done. I thought.

Customer now informs me after an hour of being on some of the rads start to get cold. A couple stay hot, some go luke warm, some go stone cold.

I'm booked in to go back to have a look but I'm now thinking that there actually isn't anything else I can probably do apart from bite the bullet and arrange for a boiler man to go in my place and pay for the fix if it was my fault..

I have drained and refilled probably about 30 or 40 combi systems in my time. Only once was the a prob with boiler on refill and the guy I got in to sort it said the fault would have happened to whomever drained it as it was waiting to go wrong. But I suspect this time I may have been remiss.

 

[GasmanxxxR1]

Just turn rads off as they get hot, get them all going one by one then rebalance system, could be airlocked. No great secret in filling a sealed system, just the same as a combi really

 

[WaterTight]

Yeah? Sounds promising. Never had an airlock on a combi. Didn't think it was possible after blasting mains round it on filling up and bleeding everything.

She reckons they all get hot for an hour though. Does that still sound like airlock?

 

[GasmanxxxR1]

Was the system dirty? Where there any auto air vents?

 

[GasmanxxxR1]

Did they only stay hot for the hour after you visited and then have not worked since?

 

[Leo21]

Doesn't sound like your fault. It may have been doing this before you started, what's the customer like? If there getting hot then cooling, its ,divertor giving up, room stat not high enough, trvs shutting down or boiler shutting down. Non of these is your fault.

 

[WaterTight]

Was the system dirty? Where there any auto air vents?

water was pretty black.

Did they only stay hot for the hour after you visited and then have not worked since?

I got the impression the get hot whenever they've put it on over the weekend but only for an hour and then variously get cold apart from one or two

Doesn't sound like your fault. It may have been doing this before you started, what's the customer like? If there getting hot then cooling, its ,divertor giving up, room stat not high enough, trvs shutting down or boiler shutting down. Non of these is your fault.

Customer seems very trustworthy, I'd be surprised if they were trying it on.

Could divertor or any other boiler prob occur because the power was still on when draining top floor? Boiler is on bottom floor if that makes any difference.

 

[WaterTight]

Where there any auto air vents?

didn't see any. how could that contribute to problem?

 

[Leo21]

water was pretty black.



I got the impression the get hot whenever they've put it on over the weekend but only for an hour and then variously get cold apart from one or two



Customer seems very trustworthy, I'd be surprised if they were trying it on.

Could divertor or any other boiler prob occur because the power was still on when draining top floor? Boiler is on bottom floor if that makes any difference.

Only iff the pump ran. Which it wouldn't iff there was no demand from the programmer.

 

[WaterTight]

Thanks guys. I'll have a crack and persuading it into life and if not get a gas safe engineer to sort.

Out of interest, what percentage of drain downs do you find you get problems with on refill? Aside from airlocks. So, boilers parts, blockages etc.. Just wondering if I'm unlucky to have got around 3 or 4 out of maybe 40-50 drain downs in total.

 

[Leo21]

That Is quite unlucky, I only get he occasional blocked feed on conventional systems.

 

[plumber0808]

Thanks guys. I'll have a crack and persuading it into life and if not get a gas safe engineer to sort.

Out of interest, what percentage of drain downs do you find you get problems with on refill? Aside from airlocks. So, boilers parts, blockages etc.. Just wondering if I'm unlucky to have got around 3 or 4 out of maybe 40-50 drain downs in total.

The ones that you think are going to be a pig to fill back up normally are.

Sometimes you can re pressurise the system bleed it and works no problems and sometimes it can take a couple of hours bleeding, pulling water through, balancing.

everytime the customer will say it worked before 100%.

A recent one of mine I changed combi filled up, one rad just not working customer says yes was working before. It was piped up with flow feeding both sides!!
"working before was it? We will say no more on that one"

 

[secret squirrel]

Never trust what a customer says, most lie through there teeth,

 

[tamz]

If you are ever draining a system with motorised valves on always open them manually when draining and filling or you will almost certainly have problems.

 

[GasmanxxxR1]

didn't see any. how could that contribute to problem?

Just thought it may have vented and lost pressure over weekend.

They stay hot for an hour then go cold.....interesting..... Go in with an open mind and just put the system through its paces, it maybe something simple

Let us know what happens

 

[Veggie Dave]

Never had an airlock on a combi. Didn't think it was possible after blasting mains round it on filling up and bleeding everything.

I've got a customer who installed his own CH, using miles of plastic (it's quite a large semi-detached) but not enough planning or pipe clips. It is impossible to bleed the system - even isolating radiators doesn't work perfectly.

It's an utter nightmare to work on.

 

[WaterTight]

After spending a couple of hours there I'm convinced any issue is with the boiler itself. When I walked in heating had been on for a while. Some rads nice and hot, some not quite hot enough. Boiler was clicking on and off every 30-90 secs. It's a Potterton Suprima. We used to have this boiler in my old house (only just twigged on looking at it this time) and had the same problem for years. Engineer after engineer tried changing bits and I even remember being told on here that they were rubbish and once been featured on Watchdog back in the day.

Turned off, went to do a job at another house. Returned once cold. Checked pressure correct, checked all bled. Once turned on everything heats up in the order you'd expect, as timely as you'd expect. No gurgling. Boiler stays on. All rads got hot within 10-15 minutes and 30 mins later we still all nice and hot.

Didn't wait to see if it would get to the point of clicking on and off again because there's nothing I can do about that. Just told her it looks like a boiler issue to me. She said she's covered by some sort of boiler plan with some company and will call them if it continues.

Hopefully that's the end of that....

 

[Leo21]

it will be, ive got to do a job on the same boiler same issue. pcb failure.