Glowworm Boiler no hot water at shower mixer

[Bob1256]

Hi new to this but have looked for similar everywhere and no joy! I have a glowworm betacom 30 5 years old. All hot water taps are ok apart from shower mixer, no hot water but when I run the hot tap a bit as well, the shower goes hot. I have replaced the mixer so won't be that and have checked the hot & cold connections are at the right valves. Also, when I run the CH the shower goes hot? I have checked the DHW inlet filter and shower filter?? Help please!

I should add, I did some pipe-work modification to the MCW (putting in 4No bends with 2No flexi-pipe) I now know this was wrong so have put everything back to as-was, still the same problem tho.

 

[FlameSafe]

it could be a diverter valve problem, 8 times out of 10, it usually fixes it. but cant promise it. its also probs the cheapest way to start to.

 

[Bob1256]

Hi,

Thank you for your reply, I have just been told it could still be the mixer... if I get a mixer with a larger delivery per min (6 l/min as to the existing 3l/m at 0.1 bar) could this fix it... with a larger flow rate to call in the boiler? Can I check the divert valve?

much appreciated.

 

[buckley plumb]

you could proove its the mixer by fitting a full bore isolatore on the pipes to the shower then turning the cold one off to see if the shower valve then has the flow to switch the boiler on .also check valve for blocked filter gauzes . just thoughts

 

[Bob1256]

Hi,

I have done that and the water flows hot so must be making the switch, the filters are also clean on the mixer and boiler DHW inlet... is this looking like another faulty shower mixer, can anyone recomend one that will work, the new one was a triton?

 

[buckley plumb]

some showers come with a variation of flow restrictors ensure they are fitted correctly or fit one that restricts more to the cold

 

[Bob1256]

I have a little more info, I have measured the flow rate on the kitchen hot water and it's above 4l/min, the boiler manual say's it should fire on 3l/min, think this will be the problem for the shower - any ideas what could cause this?

 

[SafeGasInstall]

4l /min - this is very low flow of hw
should be average about 9-10l

 

[Bob1256]

Apologies, I meant without firing, the max flow is just over 6L/min so still not the 9-10. I have a boiler guy coming tomorrow but just wondered if anyone had any ideas on why it wouldnt be firing at the min flow rate?

 

[jtsplumbing]

Are you in a hard water area ? possable that you have a blockage in side boiler, what is flow rate like on cold taps ? 4/6 Lts not very good, whats next door water supply like ? is it as poor as yours ?