I have Hot water but not central heating

lesrollins · May 4, 2012

Hello to everyone this is my first time on this forum so please be patient.

We have just purchased a house and are wondering if anyone can help with our HW/CH. We have got a ideal classic fanned flue gas boiler with a drayton tempus 3 programmer. We can select the HW with the once, twice and cont function button and the boiler will fire up okay. But when we try and select CH with any of the once, twice and cont function button the boiler will not fire up. The CH pump can be heard but the boiler will not kick in. I have taken the front off the programmer and looking straight at the back plate it as seven inserts where the prongs from the controller box fit. From left to right on number 2 is a black wire, on number 3 is a red wire, on number 6 is a yellow wire and on number 7 is another red wire. Why will the boiler not kick in on the CH mode.
In the airing cupboard where the tank is I cannot see a motorised valve it is a mains pressure hot water tank sorry forgot to look at the name. It as been fitted with two water pumps one for the CH and the other for the HW Can anyone please help

SimonJohns · May 4, 2012

Put the hot water and the heating on at the same time

You have what's known as a thermal store.

Never turn the water off.

What you have is a primitive combi boiler setup. The cylinder should be maintained at 80c and when you want hot water it goes thru a coil in the cylinder, being heated on demand.

Heating works by sucking water from the cylinder and circulating around the system

lesrollins · May 4, 2012

Is there any way to make the CH fire up the boiler by changing the programmer model etc or do I need to change the whole system.

mountainman · May 4, 2012

I wouldnt have thought that the ch pump would kick in if the thermal store (if there is one) wasn't above 60 degrees.

mountainman · May 4, 2012

IMO Les, you are clutching at straws and may waste a lot of time and money toying with something you could get sorted easily.
Why not advertise for a heating engineer in your area from this forum.

lesrollins · May 5, 2012

mountainman said:
IMO Les, you are clutching at straws and may waste a lot of time and money toying with something you could get sorted easily. not advertise for a heating engineer in your area from this forum.

I will post some pics today of the boiler and set up there must be a way of getting the boiler to kick in when using the CH on its own. The boiler is the same as in the old house I remember there being a motorised valve next to the tank because I changed it when it went kaput
It can,t be the whole set up that needs changing is it something to do the wiring that may need changing

zzzjim · May 5, 2012

If its a thermal store , its full of hot water just waiting to be pumped around .
Tell it CH , with demand on room stat .
, and pump should run . ( Only when its cooled some will boiler need to kick in )

Stay safe , and don't blow up any expensive pcbs !

lesrollins · May 8, 2012

I now understand that it is an old fashioned system and I need to set the hot water to get the radiators hot. I have done that but the HW and CH does not get that hot only warm. I have set the temp on the tank at 90 and the thermostatic control to 30 the boiler is also set at the maximum of 6. You can hear the controls, both on the tank and on the wall click when you adjust the temp. Would they still do this if they are broken, and what else would cause low temp. Thanx