Help NO HEATING!!! Johnson & Starley warm air

Joined
23 Jan 2021
Messages
16
Reaction score
0
Country
United Kingdom
I have a Johnson & Starley warm air system, and before anyone disses warm air I (normally, when it works) love it! It's a J55-65 (Modairflow Series 2) Here it is:
219902-3c349b661e50f57720d427d698c793b5.jpg

Problem is that at the moment something is v wrong... The burner keeps not firing up, despite the thermostat being turned up & the house cold (so it should start up).
Bizarely, every now & then it will spontaneously start up - sometimes just for 30 seconds, sometimes for a few minutes. Then it will stop again. The intervals between these firing-ups varies hugely. There seems to be no pattern.

Unfortunately these random (usually short) firing-ups are not sufficient to heat up the house and we are freezing!

A few months ago the burner etc was thoroughly cleaned out so I don't think it is sooted up.
And yesterday the guy who usually looks after our system replaced the capacitor, but the problem is still there - so it's not the capacitor.

So what could the problem be???
 
Sponsored Links
Joined
30 Dec 2018
Messages
10,709
Reaction score
1,445
Country
United Kingdom
Stab in the dark, is the air circulation/duct fan running?

The capacitor replaced, was that on the air circulation fan?
 
Joined
23 Jan 2021
Messages
16
Reaction score
0
Country
United Kingdom
Yes the capacitor is on the Sifan
When it does it's brief intermittent start ups then yes the fan runs. That's what I find so confusing
 
Joined
30 Dec 2018
Messages
10,709
Reaction score
1,445
Country
United Kingdom
I know almost nothing about those systems, I have only ever seen one and it was condemned because the heat exchanger had failed, but it reads as if what ever method it uses to confirm the burner is burning, is not working. It's not seeing combustion so it is shutting back down again - Thermocouple or ionisation sensor maybe.
 
Joined
30 Dec 2018
Messages
10,709
Reaction score
1,445
Country
United Kingdom
I know almost nothing about those systems, I have only ever seen one and it was condemned because the heat exchanger had failed, but it reads as if what ever method it uses to confirm the burner is burning, is not working. It's not seeing combustion so it is shutting back down again - Thermocouple or ionisation sensor maybe.

Another possibility is that what ever method uses to check if the air circulation fan is actually working has failed. Possibly a vane in the air flow.
 
Joined
9 Sep 2005
Messages
12,716
Reaction score
3,440
Location
Sussex
Country
United Kingdom
Call in a warm air specialist..these units are not for diy repairs. They're open flued and you've got a circulator which are always problematic.
Is that the correct J&S capacitor as it looks too small.
 
Joined
23 Jan 2021
Messages
16
Reaction score
0
Country
United Kingdom
The capacitor is from Torin-Sifan where J&S get their capacitors from. They said it was the correct replacement for the old one but it is true that it is physically a little smaller than the one before.
However the cutting out
problem pre-dates the capacitor replacement
 
Joined
30 Dec 2018
Messages
10,709
Reaction score
1,445
Country
United Kingdom
The capacitor is from Torin-Sifan where J&S get their capacitors from. They said it was the correct replacement for the old one but it is true that it is physically a little smaller than the one before.
However the cutting out
problem pre-dates the capacitor replacement

Components do become more compact, as time passes. What matters is the values printed on the side. If the fan starts and runs, it is fine.
 
Sponsored Links
Joined
23 Jan 2021
Messages
16
Reaction score
0
Country
United Kingdom
Yes the values match. And as you say, if the fan starts & runs I would have thought it was not the capacitor. Or could it conceivably cause it to malfunction??
 
Joined
23 Jan 2021
Messages
16
Reaction score
0
Country
United Kingdom
Ian that's a very good question.. however I will need to check when it next cuts out because right now it is having a burst of life! (and I don't want to do anything that might jheopordise that, we are getting some welcome heat)
You see once every 6-10 hours it will run for about an hour - ??**?? what could that possibly mean?!
 
Joined
27 Jan 2010
Messages
1,206
Reaction score
305
Location
Buckinghamshire, Darn Sarf
Country
United Kingdom
It could mean that once every 6 - 10 hours the burner temperature sensor does not register it as being 'hot enough'.
Ask your guy to check that, and his reason for changing its setting previously?
 
Joined
15 Aug 2010
Messages
24,962
Reaction score
11,162
Location
Livingston
Country
United Kingdom
Can you try and post a decent pic of the part I have circled in your pic, we need to see the settings

Inkedwau_LI.jpg
 
Joined
23 Jan 2021
Messages
16
Reaction score
0
Country
United Kingdom
OK so in answer to the earlier question - when I put the summer air circulation to 'on' the fan does not automatically start up. Later however (with summer air circ still set to 'on') it did it's usual random start up (burner & fan) for a while before cutting out again.

And here is a photo of that part (what is it called?). Would you believe it is mounted upside down, so the first pic is how it sits in the boiler, the second picture is rotated
 
Joined
9 Sep 2005
Messages
12,716
Reaction score
3,440
Location
Sussex
Country
United Kingdom
I'm not going to give you an answer as warm air units are normally open flued, often not fully compliant with regs are therefore less safe than other appliances. In addition you have a circulator at the side of the warm air heat exchanger and if that is still operational ups the risks as these units are often in poor condition.
Do NOT operate the unit with the front panels removed. There is a high risk that the fan will pull air from the flue rather than the purpose built return air ductwork..resulting in a carbon monoxide incident.
 
Last edited:
Sponsored Links
Top