Any combi boiler experts?
Discussion
I know a bit about plumbing, and have in fact fitted a complete central heating system a couple of years ago, but my knowledge of the innner workings of a combi boiler are pretty limited.
We have a newish ariston at home - it has been perfect until we went on hols two weeks ago and the builders came in.
They had to move a radiator, which they did and all seemed OK, but now when I turn the hot tap on, the water gets hot and then goes tepid, and stays tepid unless I reduce the flow rate massively.
I know the heating and water circuits are seperate, and that the cold weather will mean the inlet temp is a bit colder, but has anyone any ideas why it has suddenly stopped working properly before I get fleeced by a plumber (£70 an hour!!)
Cheers
Chilly Chris
We have a newish ariston at home - it has been perfect until we went on hols two weeks ago and the builders came in.
They had to move a radiator, which they did and all seemed OK, but now when I turn the hot tap on, the water gets hot and then goes tepid, and stays tepid unless I reduce the flow rate massively.
I know the heating and water circuits are seperate, and that the cold weather will mean the inlet temp is a bit colder, but has anyone any ideas why it has suddenly stopped working properly before I get fleeced by a plumber (£70 an hour!!)
Cheers
Chilly Chris
hughjayteens said:
We have a newish ariston at home - it has been perfect until we went on hols two weeks ago and the builders came in.
Can't help but do know we have an Ariston Combi boiler and it is quite easily the worst ever boiler, had the gas board out 6 times since 1st Jan!
In the process of getting quotes to change it. I suggest getting gas care cover for it, as it will be a worthwhile investment, although not all companies cover Aristons which says something!
As you say, the heating and hot water circuits are separate. Perhaps the plumber failed to repressurise the heating system but I don't see why this shouldn't affect the hot water system. Is it as simple that the temperature dials have been adjusted? 
>> Edited by jap-car on Thursday 2nd March 22:14
>> Edited by jap-car on Thursday 2nd March 22:14
Try this link - it's a plumbing forum (and sometimes I think car forums are sad!)
www.diynot.com/forums/viewforum.php?f=7&sid=2a5bf2039c0c55c0728bf320bccafce8
www.diynot.com/forums/viewforum.php?f=7&sid=2a5bf2039c0c55c0728bf320bccafce8
This happened on our Baxi combi boiler. It turned out to be a gas pressure drop. In other words the boiler was suddenly being starved of enough gas to work the 'direct' hot water side of the system. (It still worked the central heating side - no problem.)
When we investigated we found that kitchen fitting work that we had carried out had slightly crushed the gas feed pipe under the floor, thus reducing the flow.
You really do need an engineer to test for these things. However, it really can only be a gas problem (like above) or a water pressure problem. For example, there should be a water pressure control valve to measure the incoming pressure and restrict it if needed. This could be broken. (Hence why it works when you turn the tap down).
The other water thing is flow. It is possible to have enough pressure without having enough volume of water. However, if your system was working fine before then it is unlikley to be this. (Unless the waterboard are digging up the road?)
For what its worth, i hate my combi and will never have another as long as dont have to live in a nursing home and wear diapers. Water storage is sooooooooo much better. IMHO.
>> Edited by Tuska on Thursday 2nd March 22:34
When we investigated we found that kitchen fitting work that we had carried out had slightly crushed the gas feed pipe under the floor, thus reducing the flow.
You really do need an engineer to test for these things. However, it really can only be a gas problem (like above) or a water pressure problem. For example, there should be a water pressure control valve to measure the incoming pressure and restrict it if needed. This could be broken. (Hence why it works when you turn the tap down).
The other water thing is flow. It is possible to have enough pressure without having enough volume of water. However, if your system was working fine before then it is unlikley to be this. (Unless the waterboard are digging up the road?)
For what its worth, i hate my combi and will never have another as long as dont have to live in a nursing home and wear diapers. Water storage is sooooooooo much better. IMHO.
>> Edited by Tuska on Thursday 2nd March 22:34
I had a similar problem once, and it was due to the mains stopcock not being opened enough. Some work had been done in the house which required the stopcock to be turned off, and it wasn't opened enough afterwards.
Maybe your builders turned the water off? As has already been said, there was also an isolating valve on the inlet to the boiler which seemed to be used to control flow rate as well.
I've subsequently moved house and have a 'normal' heating system, but I always liked the principle of the combi, it's a shame it was underpowered (for want of a better word - i.e. can only have one hot tap open at a time), and the Ariston unit we had required about 4 engineer visits in 18 months (normally related to the sensors on the flue).
Richard.
Maybe your builders turned the water off? As has already been said, there was also an isolating valve on the inlet to the boiler which seemed to be used to control flow rate as well.
I've subsequently moved house and have a 'normal' heating system, but I always liked the principle of the combi, it's a shame it was underpowered (for want of a better word - i.e. can only have one hot tap open at a time), and the Ariston unit we had required about 4 engineer visits in 18 months (normally related to the sensors on the flue).
Richard.
Check the pressure gauge, it should be reading between 1 and 2 bar. If less than 1 bar it needs repressuring. Shut down the electrics to the system and find the cold feed, repressurise to the above and shut cold feed off again. Switch electrics back on and hopefully hey presto. If pressure is OK and still having the same problem it could be the diaphram, £80 to £100
and you won't be able to fit it yourself (I know from experience). It is only likely to be the diaphram if you ran the system on low pressure for quite some time. Hope this helps.
and you won't be able to fit it yourself (I know from experience). It is only likely to be the diaphram if you ran the system on low pressure for quite some time. Hope this helps.richa said:Whoops, just re-read the original post to find that I hadn't read it properly in the first place. That means my reply is total arse! Sorry about that
I had a similar problem once, and it was due to the mains stopcock not being opened enough. Some work had been done in the house which required the stopcock to be turned off, and it wasn't opened enough afterwards.
Maybe your builders turned the water off? As has already been said, there was also an isolating valve on the inlet to the boiler which seemed to be used to control flow rate as well.
I've subsequently moved house and have a 'normal' heating system, but I always liked the principle of the combi, it's a shame it was underpowered (for want of a better word - i.e. can only have one hot tap open at a time), and the Ariston unit we had required about 4 engineer visits in 18 months (normally related to the sensors on the flue).
Richard.
I had a similar problem with my combi, water just would not heat up no matter how long you ran the tap for, tepid just like you.
Brittish gas came and had a look, turned out to be the flow valve. It detects water going through it when you turn the tap on and heats it. It wasnt detecting the water flow so not heating it.
Brittish gas came and had a look, turned out to be the flow valve. It detects water going through it when you turn the tap on and heats it. It wasnt detecting the water flow so not heating it.
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