Problem with Salus RT 500 thermostat

[MikeSki]

We have a Salus RT500 thermostat controlling the combi boiler. It works OK on the timer but if we want a boost before having a bath we scroll the temperature up to about 30 degrees. The boiler will fire up but it switches itself off after about 2 or 3 minutes. Any suggestions? Contacting Salus Technical helpline was no help. Surprise, surprise.

 

[Chuck]

We have a Salus RT500 thermostat controlling the combi boiler. It works OK on the timer but if we want a boost before having a bath we scroll the temperature up to about 30 degrees. The boiler will fire up but it switches itself off after about 2 or 3 minutes. Any suggestions? Contacting Salus Technical helpline was no help. Surprise, surprise.

If you have thermostatic radiator valves (TRVs) these may be limiting the power that can be emitted by the radiators. The boiler may be detecting this condition and shutting down to prevent damage.

 

[TimboTwo]

" Contacting Salus Technical helpline was no help. Surprise, surprise"
Probably because there is no fault with the Salus unit.

If the boiler shuts down that quick you have a circulation issue.
Suggest you get a heating technician to attend to it.

 

[Aquarius]

Daft question, do you try and “boost” it shortly after the heating has been on?

 

[MikeSki]

Daft question, do you try and “boost” it shortly after the heating has been on?

No. Heating goes off at 8pm and we try the boost at about 10pm

 

[ShaunCorbs]

What are you boosting the heating for more hot water ?

 

[MikeSki]

What are you boosting the heating for more hot water ?

No, hot water is not a problem. We want to warm up the bathroom prior to having a bath.

 

[ShaunCorbs]

But your whole house is going to heat up so better off just adjust the program to stay on until 10.30

 

[MikeSki]

" Contacting Salus Technical helpline was no help. Surprise, surprise"
Probably because there is no fault with the Salus unit.

If the boiler shuts down that quick you have a circulation issue.
Suggest you get a heating technician to attend to it.

But the boiler will stay on for 4 hours at a time when working from the programmer so don't think there is a circulation problem.

 

[Chuck]

Does the system have a pump outside the boiler? If so, I think it's possible that you have a wiring / configuration issue whereby the Salus turns on the boiler but not the pump but the programmer turns on both. Three minutes is also a possible 'pump overun time', which may be significant from the point of view of diagnosing what the problem is.

I suggest you get a heating engineer or electrician 'who does heating controls' to investigate.

 

[MikeSki]

Does the system have a pump outside the boiler? If so, I think it's possible that you have a wiring / configuration issue whereby the Salus turns on the boiler but not the pump but the programmer turns on both. Three minutes is also a possible 'pump overun time', which may be significant from the point of view of diagnosing what the problem is.

I suggest you get a heating engineer or electrician 'who does heating controls' to investigate.

Thanks for that Chuck. I will probably do that or maybe invest in a Honeywell as a lot of revues suggest. I think it is significant that Northern Gas Heating, who installed my boiler, no longer use Salus programmers.

 

[snowhead]

Does the Salus setting stay at 30 after the boiler has cut off?
It may have settings to stop a large boost increase and or to limit the upper temperature.

Have you tried just raising the temperature by a few degrees and see if it holds the boiler on?
If so try a few more and see at what point it starts to switch off.

Has it worked in the past by boosting to 30?

 

[Chuck]

Idea deleted after more thought...

 

[spanner]

Are ALL radiator TRV,s are turned UP to MAX or different settings in places?, hoping this,ll continue the heating to work after last shut down to dissipate. How many Rads on system?
Check the timer settings??