Hot water system, water heats up but none comes out!

[600rob]

Hopefully someone can help me out with the problem im having with my hot water (or lack of)

Background info: The boiler is a Range Flowmax 180 electric boiler, manufactured in 2004 and as far as i know was first used when the flat was built in 2004.
The flat has one downstairs bathroom with sink/shower
Upstairs shower room and sink basin
One kitchen
The problemThe boiler/hot water system in my flat has never seemed to work properly.
The problem is maintaining a constant flow of hot water. What commonly happens is that the hot water tap in any of the above rooms get turned on. Initially Very hot water generally comes after a few seconds however after around 30 seconds to a minute the flow of water quickly changes from hot to luke warm and eventually it flows only stone cold water.
If you leave the tap running it the flow seems to randomly change from hot, warm and cold but more often than not its mostly cold. Theres no chance of leaving a running bath to fill up as 9 times out of 10 you’ll come back a few minutes later to find a cold bath. This used to be an occasional to regular problem but it’s now happening all the time. Ive been reduced to taking very fast showers before the water runs cold.
Ive had a look in the water tank and the water heater seems to be working. I can hear the boiler working when it’s set to come on and it is possible to lift the plastic cover from the top of the boiler and check the water level and temp inside. Ive checked the water temp inside several times and the water is well hot (enough to burn your hand) So the tank itself is producing and holdong hot water, it’s just not coming out from the tap!

Does anyone have any suggestions as to what it could be or anything i can do/check before having to get the wallet out and professionals in to look at it.
Thanks

 

[msmsm]

Note I am not a plumber, or anything like it. I am just mentioning what was mentioned to me!

I am assuming it is a combi boiler (that is how little I know). If the boiler is coming on when only hot water is flowing and heating is off then do the following:

1) Let the radiators go cold.
2) Turn on hot water and watch boiler:
a) Does it cycle on and off. If so maybe overheating?
b)If not feel the outlet pipes - is the CH flow pipe getting hot? If so then could well be the divertor valve is not switching so your hot water is going down the default route into the central heating.

Like I said, I am about as far from a plumber as you can get, but doing the above may supply some more info for the experts to get involved with.

 

[600rob]

Hello mate,

Thanks for that, however it’s not a combi boiler and there are no radiators as the whole flat is electric. I don’t have any gas or central heating in the flat. All heating comes by way of storage and portable electric heaters.

Last night I did try placing a hand around what i think was one of the outlet pipes as i got the wife to run the hot water in the kitchen.
The pipe went very hot indicating hot water flow but this lasted about 30 seconds before going cold again. While i did this there was hot water in the tank which left me scratching my head

 

[WabbitPoo]

When was the boiler serviced? It sounds likely the boiler is kaput in some way (I guess you knew that!). Might be time to call a pro.

 

[msmsm]

Ahh, ok. Sorry about that! I'm afraid I have no idea then!

Matt

 

[45yearsagasman]

That sounds like an unvented cylinder or thermal store heated only by immersion heaters.It may be that the heaters are not bringing the store up to temp or scale is an issue or maybe a blending valve problem.Either way its not a boiler fault cause there isn't one A pic of the setup would help
Just seen some info on these and it is an electric thermal store.Get all the things I mentioned checked out.

 

[600rob]

That sounds like an unvented cylinder or thermal store heated only by immersion heaters.It may be that the heaters are not bringing the store up to temp or scale is an issue or maybe a blending valve problem.Either way its not a boiler fault cause there isn't one A pic of the setup would help

Hi There,

Not a problem, ill get some pictures posted up tonight and hopefully they will provide some more information.

 

[600rob]

okay heres a few photos of the water tank/system which will hopefully give a bit more detail.

I noticed what looks to have been some sort of leak around one of the lower pipe where there is a heavy build up of scaling. There isnt any visible sign of leaving in the floor any more.... perhaps becuase all the scale has blocked the leak!

Photos are in this album:

//www.diynot.com/network/600rob/albums/7696

 

[hi1]

Something letting by, shower thermostat?

 

[600rob]

Something letting by, shower thermostat?

come again?? can you explain that one to me please.

 

[hi1]

From what i've read on the forums is it possible that one of the showers or taps thermostatically controlled can allow cold water at a higher pressure, mains, to enter the hot water side of the system, due to the defective nature of the thermostat, propelling the hot water backwards and only allowing cold to come out of the tap or shower? If the mains is finding its way back into a sealed system then this could create surges as the pressure increases in the hot water side allowing the hot or now tepid water to flow normally until the pressure drops below that of the cold mains where the situation repeats.

 

[600rob]

From what i've read on the forums is it possible that one of the showers or taps thermostatically controlled can allow cold water at a higher pressure, mains, to enter the hot water side of the system, due to the defective nature of the thermostat, propelling the hot water backwards and only allowing cold to come out of the tap or shower? If the mains is finding its way back into a sealed system then this could create surges as the pressure increases in the hot water side allowing the hot or now tepid water to flow normally until the pressure drops below that of the cold mains where the situation repeats.

Ahh i see, thanks for the explaination.

yes the upstairs shower does have a temperature control dial on it how would i go about locating the thermostat and testing it to see it its at fault.

Is it hard to repllace the thermostat?

 

[45yearsagasman]

Too many cooks etc. Fault finding is a logical process whereby you test and eliminate one thing at a time and not dash around testing so many things that you miss something simple and go looking for the hard things.I'm not saying that it will not be a fault elsewhere but you must prove that your thermal store is operating correctly to start with, and for that you need qualified help.

 

[600rob]

Too many cooks etc. Fault finding is a logical process whereby you test and eliminate one thing at a time and not dash around testing so many things that you miss something simple and go looking for the hard things.I'm not saying that it will not be a fault elsewhere but you must prove that your thermal store is operating correctly to start with, and for that you need qualified help.

Time to get a pro in.

Can anyone recomend a specialist in thermal stores that works in the south london area.

I used to have a contact for a range specialist but can get hold of him anymore

 

[Garfeild]

A simple check if you know how to shut the hot water off to the flat.
Isolate the hot water,possibly a cold water inlet supply to the cylinder.
Open a hot tap,do you still get a water flow from hot tap,even though its shut off? is the water now cold?
If so its backfeeding somewhere,probably a non return valve on the supply to the shower.