Help! No CH from Boilermate HP-DEM-A/Mitsubishi HP

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Help! No CH from Boilermate HP-DEM-A/Mitsubishi HP

Post  rubinho on Tue Dec 19, 2017 10:33 am

Hi,

I'm looking for some help troubleshooting a Boilermate HP-DEM-A.  The central heating is not working although hot water and towel rails (from heating zone 2) are fine.  The front panel displays Normal operation (but I have tried Switch and this doesn't work either) and no error codes.

The status screens are:






The internal 2 digit display shows:



Occasionally it shows this:



The dot in disp 1 is flashing in both cases.

From what I can work out the Central Heating Valve is not getting a demand.  I have used the manual override but this also doesn't allow hot water into the circuit.  The main thermostat is a standard Honeywell T6360B1028 manual dial type which has been turned to maximum.

Every once in a while a relay clicks but I cannot tell which one that is.

Any ideas what the issue is?  The installation manual doesn't have the internal 2 digit display codes and I can't work out what is wrong.  Does anybody have the internal digit code translations?

rubinho

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Re: Help! No CH from Boilermate HP-DEM-A/Mitsubishi HP

Post  rubinho on Wed Dec 20, 2017 12:24 am

Thanks for your reply. I've seen a couple of those docs but I will check out the other links too.

Situatuion worsening, the HW and towel rails are cold now too. I think residual heat in the system kept them going a little longer than the CH. HP is still running and the BM is clicking and whirring away but no heated water is getting anywhere.

The missus is going spare what with it being 5 days to Christmas!

Cheers!

rubinho

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Re: Help! No CH from Boilermate HP-DEM-A/Mitsubishi HP

Post  mike on Wed Dec 20, 2017 2:39 pm

I am afraid they are bad news.
Have you tried Gledhill Tech line?

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Re: Help! No CH from Boilermate HP-DEM-A/Mitsubishi HP

Post  rubinho on Wed Dec 20, 2017 3:14 pm

60p a minute? They're having a laugh. Blatant profiteering.

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Re: Help! No CH from Boilermate HP-DEM-A/Mitsubishi HP

Post  mike on Wed Dec 20, 2017 3:47 pm

Well at first thought yes.

But then if you look at all the boiler manufactures and British Gas

£ 36:00p per hour is not bad

Remember the wife wants it done!

Mike

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Re: Help! No CH from Boilermate HP-DEM-A/Mitsubishi HP

Post  rubinho on Mon Jan 01, 2018 5:33 am

I appreciate that but clearly Gledhill exists as a business in some form or another. Seems a bit galling that they backrupted the bit that supplied my boiler, then carried on as another firm under the same trading name but has some poor bloke sat in a room somewhere answering phones at 60p/min pretending they don't trade anymore. It's like those double glazing companies who go bust so as not to honour warranties but are up and running a week later with the same directors under a very similar name. Anyway, ethics and morals aside onto my issues.

I'm back diagnosing the problem. Hot water works fine with Switch override turned on; this is good. I have two things that are puzzling me. Firstly the s5 and s6 temperatures which are the HP flow and return temperature sensors seem to be reading low (<30°C) and I think they should be higher (C.50°C). This points to a problem with the heat pump.

Also the Grasslin timer periodically resets, a relay clicks, the screen goes blank for less than a second and then it comes back. I have reset this by using a paperclip in the little reset hole and then correcting the time/date.

It's my belief now that either there's a problem with the timer which isn't allowing things to get up and running correctly (as it keeps resetting) or the HP itself has a problem which isn't being picked up by the BM. I'm assuming that if the system temperature isn't correct the CHV won't open as there's no point in sending cold water round the system. Appreciate any pointers. Happy New Year!

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Re: Help! No CH from Boilermate HP-DEM-A/Mitsubishi HP

Post  rubinho on Tue Jan 02, 2018 4:32 am

I did a bit of digging around in the HP yesterday.  This side of things seems to be OK.  I used SW1 switch 2 to reset any fault codes.  I did notice that SW8 switch 3 was set to Off which all the Gledhill manuals have in BIG TEXT this should be turned on at commissioning by the installer.  I moved that to what the documentation says is the correct setting.  

The HP runs for only about 30s at a time.  When it does the LCD on the HP control board reads H6 (heating, level 6) and when it is off it reads O2 (off, level 2).  To me this sounds correct.  

Fingers are pointing more and more at either the Grasslin timer or the BM control board.  I'm going to yank the timer out and hot-wire the output to set CH and HW permanently on to rule this out.  

*** I will be isolating the BM at the RCD in the fusebox before pulling the timer out as it takes a mains feed ***

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Re: Help! No CH from Boilermate HP-DEM-A/Mitsubishi HP

Post  rubinho on Thu Jan 04, 2018 6:11 am

It was the Grasslin timer! Removed it, hard wired the CH and HW signals and everything sprang back into life. Toasty house and hot water with no oil filled rads or Switch override.

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Re: Help! No CH from Boilermate HP-DEM-A/Mitsubishi HP

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