Pump or stat

[tickdoc]

Hi can anyone please help with a control issue I'm not sure about. Old system no motorized valves or wall stat, just a pipe stat at hotpress. 1 circulating pump for oil boiler and fire. Boiler fires up NP but only for 5 to 10 mins so I thought pump. Householder checked for vibration when boiler turned on, no vibration so thought def pump. Now he says it is vibrating and a little heat in rads since he lit the fire. Boiler still won't keep firing unless u turn boiler stat up. I'm now thinking dodgy boiler stat although its not going onto the high limit and tripping out. Any ideas and thanks in advance.

 

[Best]

One pump for the oil boiler and fire??? That can't be right, unless the system is a DIY bodge.
I would still say it could be circulating pump. It could be vibrating but not pumping.
Check directly the pipes at the oil boiler temperature first to see if hot.

 

[tickdoc]

Thanks best, I wud personally like to fix this if I can as the guys father did me a favour with my car before. The old woman who did live in the house for 70 years says def only 1 pump. If the time clock powers the pump when boiler is running, what powers the pump when the boiler is off and the fire is only lit. Is there a sensor from the back boiler. I've no idea only oftec 101 not a plumber.

 

[Last Plumber]

This sounds like a DIY installation?

I would recommend you get a heating engineer to look it over for you to rule out any lurking dangers

 

[Best]

Definitely sounds DIY. It might be done in a stupid way with primary flow & return from
fire also linked to rad circuit and maybe some upstairs rads are working on gravity.
It is the fire side I would be worried about as it is uncontrolled.
Tell the owner not to light the fire until a heating engineer checks the system and gives advice on any issues. The pump, if it is definitely doing the oil boiler could be replaced to test

 

[tickdoc]

Thanks for all the input, safety first. While I service, repair oil boilers , replace circulating pumps , motorized valves etc I'm not a plumber so don't get involved. I have done oftec 101 and serviced and repaired quite a lot in the last 11 years. His plumber friend coming out tonight, I still think its pump, its fitted so the bearings won't get lubricated. No pump at boiler , just a pump near the fire and the elderly couple who owned the house insist 1 pump for both oil and back boiler.