Immersion Heater Thermostats Keeps Tripping

A couple of years ago I had the replacement overheat thermostat kit applied to my boiler by Mike which had worked fine, but in the last month I’ve had both overheat thermostats within the immersion heater has tripped a few times.

Is this likely to be a thermostat failure and would a replacement set of thermostats be sufficient to solve the problem?

I’ve also replaced myself the circuit board on the advice from Mike, and last year the two heat sensors.

Thanks,
Duncan

If it keeps tripping and I presumme you mean the fuse board / consummer unit.
Then it sounds like heaters.
Or is they any leaks?
EG; onto the pump or heater ( bottom)
To check the heaters you need to test them with an ohm meter.
Accross the contact of the heater 19 ohms
THen check for leaking to earth.
Mike.

Mike i have just come from a emergency call out this evening to a pulsacoil 2000 that kept blowing the mcb when the fused spur was energised. the layot on the wall was a time clock set for the two heating times and a fused spur powering the pcb and the pump.

when i opened the front cover i found water was dripping on top of the grundfoss 15/50 pump. I nipped up the heat exchanger union as this was where it was dripping from and this sealed the leak.

The bottom immersion was live thoughout fed from the timeclock but the pcb was fed from the fused spur and this was dead as the fuse had blown along with the mcb. the lower immersion was hot but no hot water from the taps.
I then disconnected the live terminal from the pump, replaced the fuse and the boiler held live, upon reconnecting the live on the pump the fused spur fuse blew along with the mcb.
I was hoping the pump which was most likely wet inside will dry out after a few days now the leak is fixed and it may fix itself. if it does not i am thinking of replacing the head of the pump leaving the unions intact.
the system has a manually fed header tank and a mains isolator above it that shuts the water supply down feeding the tank, is it straight forward to replace the head once isolated or do i need to drain the system via the drain plug at the bottom ?. any help and recommendations would be appreciated as we dont get many of these. a live to earth test of the pump showed continuity between live and earth with the supply cables removed and after using a blow dryer on it to dry it out manually the contunuity cleared but the fuse kept tripping.

HI,
Check the pump motor using an insulation tester and it will proberly fail live earth, change the head, also check the power relays are ok, also recommend an e7 meter if the tariff is general and not E7. Regards Paul.

Hi,
Had lots of those.
PHE leaking onto pump.
Not had much luck drying pumps out.
But on replacing have had Pump control pcb burn out!
So be warned!
10 out of 100 pump valves work as in turn off and not leak or are jammed.
Next is draining the unit, again the doc stick in.
Although you have 2 doc's. I use both 2 hoses are quicker.
I would say the pump is us after reading your post.
The PHE washers are next to useless, to big so they catch on the nuts. And to thin.
I have had some thicker and slightly smaller ones made, which will stand 120 c.
And they can be pulled up tight without distorting.
Mike.