Only warm water at shower

[julianyoung]

Just had new combi boiler Biasi Garda HE 28 (35deg rise at 11.7 l/min) and new Aqualisa Thermo shower fitted (35deg rise at 9 l/min). Boiler appears to work O.K. as installed by Corgi fitter. However when shower was fitted a week later there is insufficient hot water to run the shower. The shower has been fitted with the cold water restrictor for use with combi boilers. How can I do a simple check to see if the boiler is giving out its rated heat increase? A marked bucket, thermometer and stop watch spring to mind but should the DHW control on the boiler be set to "maximum" and should the hot water tap be open fully? I am afraid that, if I don't do some simple tests, the heating engineer will blame the shower manufacturer and vice versa.
Any advice gratefully received.

Julian

 

[gas4you]

Assuming it was the same chap who fitted both then he should sort it out for you without you getting to be 'piggy in the middle'!

You need to ascertain the flow rate from your hot tap, eg 11/12 litres/min, mark 12 litre level in bucket then set tap to fill this in a minute, turn dhw stat up full, take cold water temp and then hot temp and see if it has risen by at least 35D.

Do we assume all other hot taps are ok? If not could be boiler has not been set up correctly or gas pressure is low.

 

[julianyoung]

Thanks Dave,

A Corgi Fitter installed the boiler and did the initial flushing and draining. He will be back next week to do the final commissioning and signing off. I fitted the shower.
We tested the hot water and central heating after the installation but did not check the flow rate as everything appeared to work fine i.e. hot water to taps and the central heating worked on the Danfoss TP5 programmable thermostat (the boiler being in the loft.)
No checks have yet been made on the boiler or its modulation. I just wanted some pointers that I can give to the Corgi guy so that he will know what to look for and not just say that the shower cartridge is faulty (although maybe it is!) The shower is an Aquarian and by reducing the On/Off control I can increase the water temperature but the Aqualisa manual says not to use the on/off control for this purpose and anyway the shower flow obviously diminishes if I do this. It does appear that the boiler is not performing to its stated capacity and I will test the output as you suggest. If you can think of anything else I can do with regard to fault finding it would be really helpful.

Julian

 

[gas4you]

I think all the other tests will have to wait for your corgi to commission and set everything up and check the working pressure etc.

 

[julianyoung]

O.K. Dave. Many thanks for your help.

Julian