Hot water going cold

[Jbcory74]

Hi all, hoping for some advice. We’ve lived in our house for around four years and never had any issues with water pressure or hot water. However, ever since our boiler was serviced three months ago, we’ve started experiencing problems – mainly with the hot water and some with water pressure.

The hot water has become very inconsistent – it’ll be hot in the shower, then suddenly go cold, then hot again. A plumber came out and said the water was coming through too fast for the boiler to handle, so they reduced the pressure. Since then, the pressure across the house isn’t as good, and the water takes noticeably longer to heat up – it’s bad enough that guests have commented on it.

We’ve also recently had new bath and shower taps installed in the main bathroom, and the pressure from these is much weaker than the old setup. The sink tap in there (which is high pressure) works fine, and in the ensuite both the shower and tap are still strong. But overall, the issue with hot water going from hot to cold or taking ages to warm up remains. It’s also leading to water waste, especially when washing up, as it takes so long for hot water to come through.

Would appreciate any thoughts on what could be causing this! Thanks in advance.

Boiler photos added.

Also when it comes to the main bathroom…

This was the old shower (replaced because we live in a hard water area and it wasn’t suitable)

Matt Black Thermostatic Shower - Arezzo | Victorian Plumbing

Buy the Arezzo matt black thermostatic shower from Victorian Plumbing. Browse our full range of showers and shower valves to upgrade your bathroom.

www.victorianplumbing.co.uk

And this is the new set up…

Chatsworth Traditional Crosshead Top Outlet Thermostatic Bar Shower Valve incl. Rigid Riser Kit in Chrome | Victorian Plumbing UK

SHOP the Chatsworth Traditional Crosshead Top Outlet Thermostatic Bar Shower Valve incl. Rigid Riser Kit in Chrome at Victorian Plumbing UK

www.victorianplumbing.co.uk

Thank you!!!

 

[jj4091]

Was the guy who did the service the same one who said it was your water pressure. If not then get the first guy back. if it was then get a second opinion.

 

[Jbcory74]

The guy who did our service was new to the company… he ****ed it. Because when he left the boiler was leaking and I had someone else come out and they said he didn’t tighten something. But since then someone has been out twice and it’s not getting better… I’m being charged for call outs now too so it’s ****ing me off. Because the service was 3 months ago they said, but I’ve explained the issues happened since the service!!!

 

[CountryFan]

Unless a pressure reducing valve was fitted, then the flow has been reduced, not the pressure. As it’s a 38kw boiler then hot water should be excellent. So I would say you have either: a faulty mixer tap (shower was replaced), faulty TMV, blocked plate heat exchanger or diverter issue. Turn off the cold fully under the boiler and run each hot water tap in turn, if water is present at any of the outlets, this is your failed mixer/TMV, if not this then check the diverter next time it plays up, feel the flow pipe under the boiler. A blocked plate should simply be indicated on the front display by the temperature ramping up quickly. Also, does SE appear on the boiler at all?

 

[Jbcory74]

Thank you! I will send this to the plumber… it’s hard when they weren’t the one to mess it Jo maybe!

As far as I know so pretty sure nothing has been fitted. Oh flow not pressure my bad. He was turning the blue valve under the boiler - which was making the flow slower. Since I have also been playing with it but not seeing a difference…

Sometimes the hot water upstairs is ON but the boiler isn’t kicking in… and the water used to be instantly hot (near enough) and now it can be 30-60 seconds of cold water - sometimes getting likewarm, then going cold again, before going hot… it’s very annoying… but the plumber seems to think that the flow is too high and the boiler can’t cope with it… but it was not like this before the service.

Is there anything else under the boiler I could mess with? Or shall I just send your message to the plumber and let him sort? I don’t want to make it worse. The only thing I have touched is the blue valve. I’ve had the hot water running downstairs and gone to the boiler to adjust it to the flow I want…

And it all seems fine when I do that, until someone’s later on uses the shower and it goes cold after so long.

I’ve messaged Victoria plumbing already to say that the pressure is rubbish on the bath mixer and shower heads no reply yet. Maybe something is fault there. Because as I said, the en-suite has more power and so does the main bathroom sink tab…

I wonder what the engineer doing the service did

 

[Jbcory74]

No errors are showing on the boiler!

 

[CountryFan]

Sounds more and more like a faulty mixer/tmv imo. You can test this yourself as I previously described. You can keep the blue valve fully open and if it was fine before the service and water pressure in the area hasn’t been increased then it’s not that.

 

[HERTS P&D]

Thank you! I will send this to the plumber…

It's alway good to give the plumber'gas engineer a list of what the faults could be, I'm sure they will be happy with that.

Andy

 

[Jbcory74]

Only problem with this is… the hot water has been playing up since before the new shower and bath mixer were fitted in the main bathroom

Thank you. Will test this all tomorrow and let you know what happens.

I have noticed that in the en-suite the temperate knob has loosened a little but I thought that was cosmetic could that cause an issue? Surely not lol

 

[Jbcory74]

When I look at these… they both seem the same so should both have good pressure??

Matt Black Thermostatic Shower - Arezzo | Victorian Plumbing

Buy the Arezzo matt black thermostatic shower from Victorian Plumbing. Browse our full range of showers and shower valves to upgrade your bathroom.

www.victorianplumbing.co.uk

Chatsworth Traditional Crosshead Top Outlet Thermostatic Bar Shower Valve incl. Rigid Riser Kit in Chrome | Victorian Plumbing UK

SHOP the Chatsworth Traditional Crosshead Top Outlet Thermostatic Bar Shower Valve incl. Rigid Riser Kit in Chrome at Victorian Plumbing UK

www.victorianplumbing.co.uk

The Matt black one was amazing and powerful… the new one is **** compared. But the black isn’t hard wearing and the hard water messed it all up. I do not recommend black hardware!!!

 

[Jbcory74]

Also…

I have noticed from my own investigation hahaha

That if the flow is high, that when the shower runs (if it decides to kick start the boiler) I can see the temperature going up on the face of the boiler but it gets to a certain number and then drops and looks like it’s struggling???

 

[CountryFan]

Only problem with this is… the hot water has been playing up since before the new shower and bath mixer were fitted in the main bathroom

Can be any mixer

Thank you. Will test this all tomorrow and let you know what happens.

Please do

 

[CountryFan]

Also…

I have noticed from my own investigation hahaha

That if the flow is high, that when the shower runs (if it decides to kick start the boiler) I can see the temperature going up on the face of the boiler but it gets to a certain number and then drops and looks like it’s struggling???

As I said, could be blocked plate, especially if a hard water area

 

[Jbcory74]

Thank you! Are you local to Hereford you could just come and sort it hahahaha joking!

 

[HERTS P&D]

Thank you! Are you local to Hereford

Is your partner in the SAS?

Andy