Worcester 30 HE Combi

[JonM]

Sorry, think I posted this in the wrong section!

Hey guys,

Haven't posted on here in a long time! Usually just do installs but trying my hand at breakdowns this year. Been out to a fault with the above boiler. H/w but no heating. Checked the divertor valve and was faulty, so I've replaced. I'm getting heating and h/w now, but on heating the boiler gets up to about 70 degrees, shuts off, waits until it goes down to about 50 degrees, goes back into it's 'siphon fill mode' gets back up to 70 degrees and repeats this again. I'm getting circulation around the system, checked the combustion, gas pressure, resistance on thermistors, pump is spinning and can't be stopped.

Any ideas? Any help would be greatly appreciated 🙂

Jon

 

[ambrosia]

how hot is the return compared to the flow

 

[JonM]

I haven't checked that with my temperature clamps, as I was running out of time but it felt like the return was cooler. Can't say it was the right temperature with just feeling it tho

 

[ambrosia]

could be a circulation problem, check the rads for signs of sludge build up, check the resistance of the pump, (you'll need to ring manufacture for that)

also if you can disconnect the thermistor on the CH to see if it runs without it attached

had one once where it turned out that when the heating system had been converted for a combi boiler moron installers had left bypass in. i changed PCBs, ntc, said it needed powerflush, you name it till i realised

 

[JonM]

I will check those tomorrow, thank you very much.

I did some some work on this system a coupe of months ago. Rad on top floor was not getting any heat up there, turns out whoever installed it sent a return upstairs and then used the old heating vent pipe! So had 2 returns going to the rad. It's a bodge job of a system so nothing would surprise me!

 

[AlexGas]

It's a combi.

 

[ambrosia]

Alex whats the chances of airlocks in a pressurised system, i know most people on here are more experianced than me but i've never yet been troubled by airlocks with a combi boiler. have i just been lucky?

 

[AlexGas]

Sorry, it's a combi! Scrap the post.

 

[AlexGas]

Alex whats the chances of airlocks in a pressurised system, i know most people on here are more experianced than me but i've never yet been troubled by airlocks with a combi boiler. have i just been lucky?

You could be lucky. You can have an air lock with a combi, say - an installation issue.

 

[TBServices]

You could be lucky. You can have an air lock with a combi, say - an installation issue.

Very true, bit of dodgy pipework and you could be stuck for hours.

 

[ambrosia]

i'm presently stuck on a commercial installation with the boilers in the basement supplying hot water and heating to 31 millionaires flats.
had an expansion bellows burst which drained the heating system down, because of the height of the building had about 5bar + flooding the basement like a las vegas water fountain

spent a day in 7cm of standing water to get electrics boiler and subpump back on

anyway even with a microfill the heating is airlocked to f***
half the millionaires are not home or wont allow access and we cant get heating past 3rd floor

going to get our a**** chewed off monday when the boss comes back to work, but hey what can you do

anyway my point is thats a pressurised system with airlocks

Sorry Jon, i'm hijacking your post

 

[JonM]

No worries ambrosia! I did think it might be an airlock or something to do with the pipe work, as when I fired it back up after changing the divertor I wasn't getting any circulation and was chasing air round the system. But after putting it on high fire to do some tests I managed to shift it and get it circulating. Also when I worked on the system to solve the upstairs rad issues a few months ago I had it all working with no issues. So that makes me think it's either something to do with the new divertor I've fitted or another issue along side that.

I've had air locks in pressurized system before also , but usually shifted them pretty easily. Unlike gravity fed systems!

 

[gassafe]

Did you do a full drain down? Or just use the isolaters below the boiler? Surely not much air if the boiler was isolated

 

[JonM]

Iso's on the boiler, then drained out the prv as the new divertor came with a new prv. So yea not much air should have gone in