PulsaCoil A Class

Having problems getting hot water from PulsaCoil A Class (moved into new flat)

Have Economy 10 in flat. Three switches next to boiler one is clearly "On Peak Feed" and one is "Off Peak Feed" I suspect the third is wired to the timer. Do you think this is a connection to the timer ?

Not sure why a timer is fitted as I understand one is not needed if have economy 10 ?

Boost works fine, set timer for 1 hr at 8pm and 1 hr at 4am. Had hot water at 9.30 pm last night but none at 6am this morning. I was trying to identify if the problem was with the off peak immersion heater?

Will try timer on from 12am to 6 am tonight to see what happens

But could someone tell me an easy way to check if the PulsaCoil A Class is running on the timer

and how can I check if the off peak Immersion Heater is OK. Is there a overheat reset button on these IH's ?

Thanks

Brian

Tried it on timer as I said I would still no hot water any ideas please !!!

Need to check bottom heater, any sparky can test that for you.
You are getting hot water on boost so the unit seems to be ok if heated.
There are sensors on the A class no stats in the heaters.
It could be a sensor fault.
This can be checked via the ACB or PCB board.
You would need the book on the unit though.
Down load one for free at Gledhill for free.
Be warned though the A class range are all singing and dancing and hence a bit complicated.
Have a look on the home page list of people who repair.
May be one in your area.
Mike

Thanks Mike

Apologies for delay in replying, I was having off peak supply problems that are now resolved. I have tested the Immersions and they are both showing 18 Ohms, I have also tested the supply at 6 in the morning and there is an off peak supply all they way to the bottom of the off peak relay (the one on the left) the otherside of the relay there is no supply. I thought the relay must have had it so I swapped over the relays as the peak one is working. With the peak relay in the off peak relay position still no supply on the other side of the relay.

Is there a companent that should be sending a signal to the off peak relay to trip it on ?

The PCB is not showing any fault codes ? I am baffled!

Brian

The sensors tell the heater to work via the PCB
But you have checked the fault codes ?
Mike
MGC/H2O
Noefolk

That is correct, the report FF which I believe means that the fault store is empty.

Other clues I have are, the 2 digit ACB is showing s6 sensor (top) calling, On peak supply Present, DHW pump on and left hand spot below is flashing during peak supply times and as far as I can see this doesn't change when off peak kicks in at midnight because the supply isn't getting passed the relay to the Immersion or the APB board to tell it an off peak supply is present?

The board where the peak supply relay plugs in is charred and a little melted but I assume this is because the previous owners have been using the boost to heat all of their water for months and months. The peak boost supply works fine despite this.

Any thoughts ? in the meantime I will interogate the ACB again to make sure I am not missing a fault code.

Thanks for your help so far, I have very little hair left an can't afford to lose anymore.

Brian

Hi;
What I am now going to tell you
I WILL NOT BE RESPONSIBLE FOR
But you could try;
A couple of metres of 1.5mm 3 core heat resistant or butyl flex fitted with a good quality plug top MK is good.
1st connect to bottom heater and see if that is ok, just to confirm.
Then take off peak flex out and connect in there.
One you will have a supply to work with.
Two you will get a bit closer.
BUT YOU MUST KEEP YOUR WITS ABOUT YOU AND CONCENTRATE.
Any charring or burning means that want changing the relay and base plate what have you.
I WOULD DO THAT FIRST.
Take heed of what I have written.
Mike
MGC/H2O
Norfolk

Mike

Totally understand your cannot be responsible, I agree your not.

I will keep you posted on how it goes and what I find, it may help others. Great site by the way and great to see someone committed to keeping these sort of sites going and responding promptly as you do !!!

I'm in Essex, if I was closer to Reading I would watch you sort it and learn something

Thanks

Brian

Mike

There is a reference in the fault finding section of the manual to a overheat thermostat and it is shown as item 12 on the standard equipement picture and parts list. I cant find it on the boiler as it's not in the p[osition shown in the manual and I can't find it on the circuit diagram. What does it look like and where can I find it. There is no instruction on how to reset it. Does it reset automatically when you reset the whole pulsa coil unit?

I presume it if would cut out both Immersions so this cant be the problem as the boost is working. Is there any other thermal cut outs I should be looking for that just cut out the Off Peak?

Cheers

Brian

Mike


Thanks for your help. Problem solved cost £7.45 inc VAT. It was the R3 relay as shown on the circuit diagram (in manual which is downloadable from the Gledhill site and from this site). Part obtained from Compass Direct Parts (Dagenham Essex) 0208 595 4170 part number RM87N-2311-35-5230 or also known as XB424. Can also be bought from Geldhill tele 01253 474444 but was more expensive they qouted £20.00 plus £8 carraige plus vat.

How I arrived at conclusion, with Mike's considerable help, I summarise it to help others.

I had no off peak hot water. I checked that the lower Immersion was OK by putting a multi meter across it live and neutral connections while the power is off at the wall spur. It read 19 Ohms which is about right. I checked I had off peak supply to input of relay 2 and there was but there was no output from relay 2 during off peak hours (12pm to 7am) so ( I turned the power off) I swapped relay 1 & 2 to check that relay 2 had not burnt out. (I knew relay 1 worked ok because the peak boost was working). with off peak power back on still no output from relay 2 position (with the working relay 1 in it's position) so now I knew it was not a problem with the relays 1 or 2. All sensors code stores were showing FF so all empty so no fault codes present and all set point correct. You can check these on the 2 digit LED display on the Circuit Board using the instruction in the manual.Therefore the boiler thinks everything is ok (it just don't work).

Given that all sensors are working and relay 1 & 2 are working the only reason, that the current couldn't get past Relay 2 to the Immersion heater must be that relay 2 wasn't getting the signal to switch itself to close the circiut to the off peak supply, must be that the relay 3 wasn't switching to send a cuurrent to the Circuit board to tell it to send the current to Relay 2 to switch it and let the current through to the Off Peak immersion. The only other explanation was the circuit board was burnt out (expensive if it was true). I pulled out relay 3 which is the small white box next to the incoming off peak power supply. Make sure appliance is isolated by switching off power at all of the spurs or the fuse box/consumer unit. The Relay 3 is on the DIN Rail Assembley have a look at the pictures in the manual you will spot it.

When I pulled it out one of the 5 pins was bent over and not in it's slot. I could have straightened the pin but bought a new one instead.

Thanks a million Mike, I hope this helps others. Maybe a quick check of all 3 relays is a starting point in future, once you know you have a working off peak supply. D'Oh.