Changed tap - now no hot water

Kim_kim

My daughter & her family have no hot water, it's likely they will need to call British Gas out on Monday - but in case anyone has any simple ideas I thought I would post here.

They had a mixer tap in their kitchen & bought a new mixer tap (a pull out shower one). Her partners dad & his brother came to swap the old tap for new today.

Something went wrong in the fitting & now they have only cold water.

They have a combi boiler & there is no hot water (or indeed cold water) coming out of any (upstairs or down) hot taps.
Cold water is coming out of the cold taps.
The heating radiators work.

Any ideas?

kerri_gt

This is what Baxi say on their website

Combi boilers provide central heating and instant hot water from one single unit. So if your central heating is functioning perfectly, but there's no hot water coming out of your taps, it can seem a bit of a mystery.

Knowing a bit about how your boiler works may help to explain why your 'hot' water isn't hot.

Diverter valve

Given the multi-purpose nature of a combi boiler, the appliance needs a way of switching heat from your radiators to your hot water (and vice versa). The diverter valve is the key to controlling this action.

When you turn on the hot tap, the diverter valve opens to let water into the heat exchanger temporarily closing off the water used for your space heating. When you've used the hot water, the valve switches back to divert heat back to your radiators.

If your hot water is not working, it's possible that the diverter valve is either worn, faulty or just stuck in the 'radiator position', therefore not allowing the water to heat up in the first place.

It's also possible (especially on a cold day) that your boiler is suffering from a low flow-rate, and just needs more time to pass water through the heat exchanger. Try running the tap slower, and you may find the problem solved.


Silly question perhaps but they have turned on any isolator valves they turned off to change the taps? Is the pressure on the combi reading normal?

Kim_kim

They said they've turned everything back on.


Re diverter valve, could this have happened during the tap change?
It was find till the tap was changed, it's a new boiler, only installed a couple of months ago, by British Gas

Ectophile

Kim_kim wrote: »

They said they've turned everything back on.

They say they have turned everything back on, but that doesn't mean they have.

If no water at all comes out of any hot tap, then my suspicion is that they isolated the water supply to the boiler before doing the work, then forgot to turn that back on.

If it was the diverter valve, I would expect cold, or slightly warm, water to come out of the hot taps.

Owain_Moneysaver

It's possible that the stopcock they turned off has broken internally and isn't turning on again.

Kim_kim

Ectophile wrote: »

They say they have turned everything back on, but that doesn't mean they have.

If no water at all comes out of any hot tap, then my suspicion is that they isolated the water supply to the boiler before doing the work, then forgot to turn that back on.

If it was the diverter valve, I would expect cold, or slightly warm, water to come out of the hot taps.

Dry as a bone.
I did suggest this, that they turned off a stopcock that they've forgot to turn back on.
So if it was the valve their should be some water?

southcoastrgi

if you have no water coming out of any of the hot taps then the water isn't going to the boiler, check the isolation valve is on on the boiler on the cold supply into it, look at the boiler manu to see which one it is

Le_Kirk

Two things: -
1. Try a tap upstairs, if no hot water there, then problem could be diverter valve or no water to boiler as already suggested. If there is hot water there, problem is not with boiler.
2. Check the specification of the tap, some of the mixer types require a certain pressure before they will work. I nearly fell into this trap recently when changing my kitchen mixer but just spotted the rating on the tap in time.

southcoastrgi

if there is no water at all it won't be divertor valve
the hot is off the main so it won't be that either unless the pipe is kinked under the sink

Kim_kim

There are two hot taps upstairs in the bathroom - ALL hot taps are dry.

Le_Kirk

Kim_kim wrote: »

There are two hot taps upstairs in the bathroom - ALL hot taps are dry.

I would suggest that water is not getting to the boiler then. Not sure how, maybe ask the tap changers EXACTLY what they did. There is a possibility - already mentioned - that the stopcock, which would have to have been turned off to change the tap, has not been turned back on again fully or is jammed shut. It does happen.

EDIT. Just checked back, you say you have cold water in kitchen, so my comments about stopcock are null & void. I guess you need to trace the cold water feed to the boiler.