Advice needed - faulty heating programmer or something else?

Hi

I believe our heating programmer might be broken but not sure.

Property : 2 bedroom, 2 bath flat on 6th floor of purpose built development, 5 radiators, 2 towel rails

Background : turning heating button off on "controller" (rather old Danfoss randall, picture attached ) in summers didnt turn the heating on towel rails off. We managed to turn radiators off via the radiator valves by setting them to 0. I wanted to call for help at that time but it wasnt a break down of hot water and i didn't want to invite anyone into our home necessarily during Covid time.

Situation now : we have hot water & heating works in all but living room. Living room radiators are cold. Pipe running to the TRV is hot. I have ensured that the TRV valve is moving up and down having done some youtube-ing.

1. Is the controller problem and 2 radiators not working now related? I feel they are not because pipes coming into those radiators are rather warm. its the radiators that are cold

2. Is heating programmer something i can change easily or a boiler engineer is needed?

3. Can you please recommend what will be the minimal effort replacement of the programmer that I have right now? Unfortunately, this picture is all the information i can give you on the programmer.

 

Have you bled the radiator in the lounge?

This rad not getting hot is not a programmer issue.

It might not be the programmer at fault, it could be a faulty 3 way valve, assuming your on a Y plan heating system

 

Yes , radiators were bled today.

I switched off the boiler and then when switched on, i can confirm that pipes running up to those 2 rads were rather warm.

now - about 30 minutes later, the pipes are cold again.

@sxturbo - how do i confirm if i have a Y plan heating system? I am not sure i know what is a 3 way valve.

 

If all radiators except living room are heating up it's not your programmer.
I doubt you have zonal heating ,but it's possible.
Try this ,with heating on turn off every other radiator by its TRV except the living room . See if they now heat up fully.

 

Check out this link which explains heating system design

https://www.flameport.com/electric/central_heating/heating_wiring_Y_plan.cs4

Have you balanced the radiators?

 

Thanks @terryplumb . its a 20 year old property, Boiler was replaced in 2015. the installer didnt mention a word about heating zones. so i am likely to assume lets not go there.

I will give this a go NOW.

 

Is the lockshield valve at the other end of the radiator to the TRV fully open/ fully anti-clockwise?

Could be an air lock - try turning other radiators off, all except the one without a TRV, that might clear it.

Last possibility, is the pipework choked up with debris if there is no inhibiter in the system.

 

@sxturbo - that Y plan is a bit too technical for me. I have never done balancing of radiators. I saw the phrase this evening when I was going through some forums. Should i have done so?

 

@Harry Bloomfield : Thanks for the post.

I tried with one of the rads lockshield. When i removed the white plastic cap, I saw a valve with a screw head which was rather different from all youtube videos. On videos i saw an 'alens key' like head. I took a scredriver and tried to move anticlockwise but that screw wouldnt budge. I didnt put too much pressure because I didnt want to mess things up. especially on one of the coldest days of the year.....

This is happening at this very moment. I have turned off the 3 good radiators. let's see. I will wait another 10 minutes and update this thread.

Could be true. power cleaning was conducted about 3-4 years ago, inhibitant was used and there was a magnetic cleaner thingy installed as well at that time. Since then I havent done much, so if debris have built up again, you could be right. Can it go that bad in 4 years time though ?

 

I asked you To turn off ALL other rads by their TRV's. Not just some of them . If any do not have a TRV close their wheel heads .

 

I thought living room rads were to be left on. I did that. observation to report is that pipes to the TRV went hot again but rads still cold. other observation is that rads arent ice cold. it's 3 degrees today, rads are cold but they arent like a cold slab of iron that i would expect on a day a like today.

I will do the experiement of turning all radiators off next. How long should i keep them off for?

 

Leave living room rads ON.( Both their valves ON)
Turn OFF ,EVERY other rad by their TRV or wheel head if they do not have a TRV. Is that clear ?
Run heating like this for ten minutes ,and during the ten minutes ,periodically look at boiler to see if it's continually burning gas ,most of the time.

 

right so did that. pipes running to the 2 faulty rads turned hot but rads remained cold. As i mentioned earlier, not ice cold slab of metal though.

I didnt observe the boiler's control panel explicitly. will re-do this tomorrow morning and report here.

out of interest if the boiler is burning gas through that, what does that tell us? There is hot water as well isnt it?

 

Was your programmer set for hot water whilst doing the trial ? I really just wanted the central heating running.
I suspect your TRV's on living room are stuck closed .Did you remove the plastic actuator heads ,and press down on the centre pin of the metal valve body ,which should move up and down a few millimetres ?

 

I think its my lack of attention to detail! I will do this test tomorrow : turn off hot water on programmer, ensure heating is on, turn off 3 good radiators and leave 2 faulty on and see if boiler is firing up in the 10 minute period and flame sign is on the panel.

About the TRV : yes i did that check. upon removing the plastic cover, i can push the valve down by my thumb and movement up and down seems without friction and displacement is few millimetres.