OK guys, I have almost ran out of options.
Prima 70F, 2x 2 port vales, room stat, programmer, frost stat, open vented etc.
Owner moved in 6 months ago and ever since he has had to reset the overheat stat daily. He noted that the rads had large cold spots at the bottom so these were all flushed and inhibitor added. This was early this year, and now the rads all heat up nicely etc
However, the OH stat still trips. So, the pump head go changed, so has the pump overrun stat last month. This helped slightly, but it still trips. Today, I tried to replicate the fault, so i linked out the live and switched live to force the boiler on while the valves are shut to prove the bypass is ok, and monitored the flow/return temps. It got to a maximum of 85 on the flow and the boiler stat then cut it off, and the pump ran until the temp got to 55C No matter how long a ran it (2 hrs), either linked out or otherwise, it would not trip for me. (bypass is set up correctly)
So, left with no other avenues, I replaced the overheat stat thinking that since its been getting reset daily for pretty much 6 months it might have become lazy and just popping when it feels like it, and while i was at it i changed the boiler stat too just to rule this out in the future.
Does anyone else have any other ideas?
(Gas safe engineer)
Prima 70F, 2x 2 port vales, room stat, programmer, frost stat, open vented etc.
Owner moved in 6 months ago and ever since he has had to reset the overheat stat daily. He noted that the rads had large cold spots at the bottom so these were all flushed and inhibitor added. This was early this year, and now the rads all heat up nicely etc
However, the OH stat still trips. So, the pump head go changed, so has the pump overrun stat last month. This helped slightly, but it still trips. Today, I tried to replicate the fault, so i linked out the live and switched live to force the boiler on while the valves are shut to prove the bypass is ok, and monitored the flow/return temps. It got to a maximum of 85 on the flow and the boiler stat then cut it off, and the pump ran until the temp got to 55C No matter how long a ran it (2 hrs), either linked out or otherwise, it would not trip for me. (bypass is set up correctly)
So, left with no other avenues, I replaced the overheat stat thinking that since its been getting reset daily for pretty much 6 months it might have become lazy and just popping when it feels like it, and while i was at it i changed the boiler stat too just to rule this out in the future.
Does anyone else have any other ideas?
(Gas safe engineer)
