HRM wallstar combi hot water issue.

[Crossfred]

Evening all. I should start by saying im not a plumber but i think im a reasonably competent diyer if thats not a contradiction in terms. We have a wallstar combi thats about 10ish years old. Its been serviced over the years by a local plumber. About a month ago it started playing up. Rads work fine. Hot water to the taps work intermittently. The plumber told us it was the diverter diaphragm and fitted a new one. The pressure cylinder also kept losing pressure apparently and as he had one he had already got he fitted that too and said hed come back in a week to see if pressure was ok but water was working more consistently but still not not up to scratch so we waited for his call. No call. So i rang him and he said not sure what it is and im moving away. I then tried to find a plumber with experience of hrm wallstars with no luck. I rang hrm for a couple of names but they didnt have anyone near us - we are 20 miles north of london! So i asked what they thought. They said diverter diaphragm. Been there i said. No luck. They said best way to check that is unclip the microswitch from end of diverted and turn on hot tap. Rod should project. I thought i could check that. And It does project and retract when hot tap off. They also said stick a small tool into the microswitch when hot tap open and see if pump and boiler fire and water heats. I did. And it does. Theres also the 1 bar pressure in the boiler they mentioned and 1 bar in the pressure vessel. When i hold the microswitch in we get lovely boiling water. But clip it back on and it will fire up the hot water first couple of times then
run cold again. Its almost like the diverter rod is losing pressure on the microswitch after a few minutes. Or theres some kind of sensor saying thats enough of that and closing the diverter. The pump and burner remain running but water cools to cold again. Thats the depth of my experience. Any advice welcomed. Also appreciate advice on wether to carry on diagnosing/playing with it or seek a hrm familar plumber. Thanks all

 

[lance]

change the whole diverter valve then, the diaphragm is only on the end bit.
if you are getting hot water by frigging the micro/sw, then that rules out plate ex and mixer valve.
its only money.

 

[Crossfred]

Thanks for the comment. Turned out the microswitch comes apart. Inside are two switches. The diverter valve rod pushes them on under pressure when demand is there for hot tap and they spring back off and the rod retracts back into the valve when tap off. The small plastic 'paddle' that the rod pushes had bent under the heat and pressure over the years so the rod couldnt reach it. I thought about replacing the unit. Expensive. But a small flat piece of plastic stuck on the face of the paddle sorted it and its worked ever since. Cost about 0.05p and masses of smug satisfaction gained. I have to keep trying it over and over. Cheers.

 

[PhoenixServices]

You also broke the law by taking the casing off the boiler. And I'm surprised hrm gave technical advice to a non-gsr

 

[SimonG]

You also broke the law by taking the casing off the boiler. And I'm surprised hrm gave technical advice to a non-gsr

Thats because its oil.

Oils alright though!

Oh, no, thats right, theres still a chance of killing everybody in the house if you mess about with it.

 

[Crossfred]

Im not daft enough to play around with dangerous parts of a boiler. Hence employing a plumber in the first place. But fixing a microswitch under advice from the manufacturer is within my ability. Proven. And yes poster you are right. After months of fiddling by a registered plumber and a fair amount of money this now poses a real danger to my household. Scalding to death in the piping hot water we now have. Last post.

 

[PhoenixServices]

If it's oil my bad, stick your fingers in all you want. Oftec won't slap your wrist like gas safe.

 

[SimonG]

How is your ability proven, the things not working, tis not why thou posted hither?

 

[OilBoy]

You also broke the law by taking the casing off the boiler. And I'm surprised hrm gave technical advice to a non-gsr

Yeah oil and you don't need to be Ofeck registered either, you just need to be competent. There is a small sector of my customers, mainly farmers who fiddle with their burners, then I get invited to come round and sort it when they break it.

 

[Dotty]

Farmers. The bane of every oil man's existence. ...