Boiler stove issue?

bootser

Hi All, my in-laws have a small boiler stove installed in their kitchen the last 3 years, since going in the DHW tank gets very hot but the rads rarely get better than warm(they also have oil heating).
A couple of weeks ago the stove and pipes started to make banging noises when it got very hot. Rang installer and he said either pipe stat or circulating pump was gone.
So, I called down yesterday to check both. The stat was set to 70 deg and when I turned it down to 0 it started the pump. Both seemed OK to me, so we lit the stove and waited for it to heat, when the pipe leaving the stove got very hot and the noise started I turned down the stat until the pump came on - 40deg (I had also turned the pump up to full speed).
The result was the rads all got hot quickly, Great. watched it cycle a couple of times and walked away.
So, whats the problem?? Now they have no hot water!! Im thinking to turn down the pump speed but im hoping some knowledgeable people hear can tell me if im right or what would a better change to make would be??
TIA:)

Blowheads

The stat should be as close as possible to the stove to kick in when the water gets up to temp. The banging and hissing is the water in the stove boiling but it has nowhere to go since the pump isn't running because the pipe stat hasn't called for it.
There is no exact solution.
1. Move the stat as close as possible
2. Reduce the stat to something like 55 (means the pump kicks in sooner
3. Leave the pump setting on 3 to get the water circulating as much as possible
4. Don't start a mad hot fire until the pump starts running

Make sure that everyone knows when the stove is banging to turn down the stat until the pump is running and turn it back up again after to 55ish

Lenar3556

Poor heat in radiators, and a very hot cylinder may suggest balancing could be improved - that the flow through the cylinder is too great and would need to be restricted by way of a valve.

Is the pipe stat a long way away from the stove?

Sludge in the system affecting circulation is another thing that would need to be ruled out given the symptoms you describe.

Not sure why the cylinder has suddenly stopped heating. Is there a motorised valve on the coil by any chance?

mightyreds

think you have the same plumber as myself, last 2 times he's been over he turns the pump up to 70 and same thing no rads get hot , had to go turn it back to 55 to get everything going, both times took me a bit to figure it out.

bootser

Hi All,
Thanks for the replies and sorry for not getting back sooner!!
So what I'm doing now is setting the stat around 55deg(its about a meter from the stove) with the pump on medium and the noise isnt get a chance to start at that. The hot water isnt great but the rads are getting warm consistently now, so the in-laws are happy enough. I'll update if theres any change going forward.
Cheers All!