Intergas combi hot water temperature

[Johntheo5]

Any update on your problems @tfspark ?

 

[tfspark]

Any update on your problems @tfspark ?

A quick update on the shower.

Mira sent me a control pcb, a primary valve assembly and a thermistor.
The valve assembly takes the hot and cold water and blends it to the target temperature. I fitted that and the thermistor.
I didn't fit the control board as it already had one fitted in January for the same fault.

Probably wishful thinking but the shower feels hotter to me, and no sudden cold shower so far.

I have done nothing with the boiler yet. From all the calcs in this thread it does appear to be under performing but if the shower is fixed I'm unsure whether to persue it.

 

[Johntheo5]

A faulty shower thermisor might certainly cause a problem if it caused the HW to be shut off which in turn would shut down the boiler burner.

For interset, can you post a photo of the removed valve assy. as it looks as if its electronically controlled and not just the normal thermostatic type,
I can't find any ref/photo in the spares listings.

I don't see why you shouldn't at least find out what the DHW output of your boiler is, if its 36kW then you will get a useful ~ 24% more flow and fill the bath faster.
The shower doesn't know where its supplied from, could be a UVC with "limitless" supply of HW, the MIs state a nominal flowrate of up to 16.0LPM,
At 36kW and mains of 10C, the shower should supply 14.74LPM at 45C (dT 35C) as long as your hot and cold pressures are sufficiently high enough.

"Mira Digital Mixing Valve High Pressure/Combi (not suitable for pumped gravity systems) Thermostatic Standard TMV 2 - HP (BS EN 1111 Type 2) Nominal Flow Rate Valve capable of up to 16 l/min @ 1 bar"

 

[tfspark]

Here is a picture of the primary valve assembly. Hot water into the inlet top right, cold into top left. There is a thermistor in the hot part which looks like it can't be replaced. Valves are controlled by the two motors.
Blended water then comes out the bottom outlet into the next ducting. This is where the other thermistor is, which I replaced.
Next is a flow meter which measures the volume of water used, and finally the outlets to the shower heads.
Mine is a dual outlet so you have a choice of large fixed rainshower or hand spray. These are controlled by solenoid valves.
Everything plugs into a control circuit borad.

 

[tfspark]

Just had a 15 min conversation with Intergas Technical. Basically I asked the for the DHW output of this boiler and was quoted 33kW.
I then gave him my flow and temperature figures from all taps measured, which all work out to (way) less than 33kW.

I am getting an engineer visit on Friday to check gas rating and to see if there is a heat transfer problem.

 

[dilalio]

Friday to check gas rating and to see if there is a heat transfer problem.

Yep.
Gas rate tells all.

 

[dilalio]

Not sure how “the plot thickens”. If you’re referring to the replacement gas valve that was done over three years ago. I had a few problems with the boiler in the first year and had to get Intergas to repair under warranty. They were the only ‘professionals’ I could call on.
I’ve alway thought from day one that there wasn’t enough hot water at the bath. All this has only come to light because the Mira engineer suggested the boiler wasn’t producing enough hot water.
You say “if” there is a fault. That’s the whole point of the thread. I’m trying to establish if there is or not.

Maybe my smart shower is not as smart as I thought it was.

I merely meant that, in order to properly diagnose a fault, we need all the facts... Without being there, we have to rely on what posters put in their messages!
Even the most insignificant red herring can completely change the fault identification...
it's well known that you have to ask customers what the symptoms are, and then use experience to syphon out what's relevant and what's not - and that's when you're on site!
It involves some psychology which we never get recognition for

 

[Johntheo5]

No harm to get the flue gas temperature as well which is a very good pointer to boiler efficiency but not max output.

 

[tfspark]

I merely meant that, in order to properly diagnose a fault, we need all the facts... Without being there, we have to rely on what posters put in their messages!
Even the most insignificant red herring can completely change the fault identification...
it's well known that you have to ask customers what the symptoms are, and then use experience to syphon out what's relevant and what's not - and that's when you're on site!
It involves some psychology which we never get recognition for

Thanks dialio, point well made. I was a service engineer for 40 years in a different industry. Nothing like experience to make up for the lack of information sometimes.

 

[Johntheo5]

You have supplied plenty of relative information at any rate.

 

[mcmoby69]

What is the boiler stat set to for the radiators?

 

[tfspark]

What is the boiler stat set to for the radiators?

Boiler flow temperature is 60°C, if that's what you're asking?

 

[mcmoby69]

Boiler flow temperature is 60°C, if that's what you're asking?

Yes. I'd lift that to 70 tbh.rads need to get to about 55deg before convection starts occurring. Had a few customers who turned their hre's down to 40 deg on the heating side and it affected their hot water.
I don't deal with many exclusives, mainly hre and eco rf.
Don't see the point in having an over complicated white box that makes water hot.

 

[Johntheo5]

Just had a 15 min conversation with Intergas Technical. Basically I asked the for the DHW output of this boiler and was quoted 33kW.
I then gave him my flow and temperature figures from all taps measured, which all work out to (way) less than 33kW.

I am getting an engineer visit on Friday to check gas rating and to see if there is a heat transfer problem.

Did the Engineer visit you yesterday?

 

[tfspark]

Did the Engineer visit you yesterday?

Intergas engineer did visit yesterday, and was here for about two hours.
His conclusion was he could't find anything wrong.

I don't know exactly what he did as I just left him to it. He said he'd measured flow and temerature into the bath and he also did the timed test at the gas meter a couple of times. He did spend a lot of time at the boiler itself though.
He said the results of his timed gas tests were 32.7kWh (which is the dhw rating of this boiler?), and very similar to my own test results. This seemed to satisfy him that the boiler is working the way it should.