Hot water supply problem in one room

[Alison556]

I've previously done a couple of posts on my recent hot water/central heating problems but I thought I'd be better trying to put it all together.

Started about a month ago when our Mira Excel mixer shower wasn't getting hot - who wants a cold shower in the winter.

I got the Mira engineer out as the shower was still under warranty and he reckoned that the problem was with the boiler as he noticed that there was no hot water coming through the bathroom sink tap either.

I phoned the gas engineer out to have a look at the boiler (it was a Ravenheat CSI85T) and he replaced a diverter valve.

That didn't fix the problem and the boiler leaked after his visit.

So, we got a new boiler - got a Worcester 28i Junior installed on Wednesday, along with a Horstmann wireless room thermostat.

Thursday was marvellous because we had full running hot water and a hot shower and the room stat was working beautifully. Bliss.

Friday morning, I thought I smelled gas but wasn't sure but my aunt came in for a visit and the first thing she said was that there was an awful smell of gas.

So I got the gas man out again and he checked and said that there wasn't a gas leak, sometimes you got a whiff of gas when the boiler fired up and particularly so on a windy day.

Friday evening, we were absolutely dying of heat exhaustion and I found that the boiler wasn't switching off when the room stat had reached the set temperature. I checked the room stat and receiver and they're definitely connected - the temp was set to 17 degrees and there was no call for the boiler (no flame sign showing) but the boiler was still on. If I turned the temperature up on the stat, the flame sign came on but the boiler was still on, so I reckoned that the problem wasn't with the connection from the room stat to the receiver, but more from the receiver to the boiler.

So back we went to switching the boiler off and on manually or on timer.

Saturday morning, jumps into the shower and nearly froze to death - absolutely freezing - so here we go again. No hot water in the bathroom even though the boiler is firing up when the sink tap or shower are switched on.

The heating wasn't on at that point, so I turned the heating on and waited half an hour and lo and behold, there was hot water in the bathroom. Turn the heating off and no hot water in the bathroom. The kitchen sink has been consistently fine all through this.

The boiler is also making a strange noise - like a kettle bubbling and boiling and the flue outside is making the same strange noise.

I'm at a loss to know what to do. The service engineers are coming out and looking at the boiler and telling me it's fine but there's a problem somewhere but where, I don't know.

I've got to wait till Monday for the service engineer to come out again as this isn't an emergency as we still have heating and hot water in the kitchen.

It's a flat we're in, so bathroom and kitchen are all on the same level - in fact, they're right next to each other.

Does anyone have any thoughts? I'd love to be able to throw my tuppenceworth in with some idea as to what could be wrong. I'm heartily sick of it to be honest.

 

[ChrisR]

sometimes you got a whiff of gas when the boiler fired up and particularly so on a windy day.

WHAT?
ABsolutely impossible unless you have a window open. Then it would be any time, not just when lighting.
It would be "fumes" not gas.
If that's coming in a window more than once in a month of Sundays, it''s WRONG!

The hot water thing - is there a mixer tap in the bathroom, at the basin or on the bath? Could be faulty, with a "let by" allowing cold to stop the hot. Common.

 

[Alison556]

That's what the gas man said - about the smell of gas that is. Funnily enough, he said he tightened something up and the smell has gone - but there was nothing wrong according to him.

It's a mixer tap at the bathroom sink along with mixer shower in enclosure.

If the tap at the sink was faulty, would that affect the shower as well?

On the odd occassion that we do get hot water through the sink tap, it has no effect on the shower at all - it's still pretty cold

 

[ChrisR]

tightened something up

Condensate pipe - white, thumb thickness, shouldn't have been loose.

If the tap at the sink was faulty, would that affect the shower as well?

Yip.

Try ... turn off the hot water under the boiler. Actually it's the cold inlet to the boiler. There's a quarter turn thing, see boiler manual. Open kitchen hot tap. You should have no water coming out.
Open basin tap a little - play with it, just cold then cold + hot position. If any water comes out of the kitchen hot tap, you found your problem, it's crossing over in the basin tap. The cold pressure is higher than the hot once things are running, so the cold stops the hot.

Half baked solution may be a non-return valve in the hot water pipe to the basin hot , but really you need a new tap.

 

[Alison556]

Fab, thank you, I'll try that. It's no problem if I need a new tap.

Just got to sort out all the other bloomin problems.

 

[Alison556]

I can't see anywhere to turn off the cold inlet to the boiler

View media item 69819
View media item 69820

 

[Madrab]

The Domestic cold water inlet should be the 2nd pipe from the right, 15mm pipe size. The isolator will be up just below the bottom of the boiler itself.
What you pictured is what looks to be an automatic bypass.

 

[Alison556]

It's like spaghetti junction in there and I don't have the confidence of knowing what I'm doing to try and do it

The service guy is to come out tomorrow so I'll ask him if he'd maybe do it.

 

[Alison556]

I think we have it sorted!!

Room stat - the spark had left a power loop (I think that's what the gas man called it) in where it's connected in the boiler. He removed that and it works!!

Hot water problem in the bathroom - I asked the gas man to do what ChrisR suggested and the tap wasn't the problem - but the water pressure was phenomenal so gas man shut the stop cock off slightly and we have hot water again. If I remember rightly, a few weeks ago, Scottish Water were out and bypassed a pressure reducing valve in the street, so I'm assuming that doing that increased our water pressure and caused the problem with the hot supply.