Gerkros Coseyman

Wearb

Was called out to a breakdown on this. Fault was a PC.

Here is my question; the stat -pictured- only turns on the circulating pump when the temperature rises to setting on the stat. This means that boiler has to be fired up and the water in the pipe that stat is connected to has to reach 20C (it was 30C I just turned it down to check.) before circulating pump cuts in. This seems strange to me.
Any explanations please?

jimf

pump overrun must have been having problems with nuisance lockouts on the high limit stat

Wearb

Thanks Jim. It it normal to have boiler starting without circulating pump running? Heat has to travel DOWN this pipe to activate the pump.

jimf

it will have a permanent live to keep pump running after clock time off this helps to dissipate the heat away from the boiler thus stop the hl stat from activating gerkros do have this issue seen a few if set above 65/70 trip the hl stat

Dtp1979

jimf wrote: »

it will have a permanent live to keep pump running after clock time off this helps to dissipate the heat away from the boiler thus stop the hl stat from activating gerkros do have this issue seen a few if set above 65/70 trip the hl stat

Kinda silly though. Wouldn't it cool all the rads And even the cylinder a little

jimf

you may well have a valid point but what kind of a temp drop are we looking at dtp

Dtp1979

jimf wrote: »

you may well have a valid point but what kind of a temp drop are we looking at dtp

In the cylinder, no idea. In the rads shur they'd essentially drop down to whatever the stat is set to. In this case, 20 or 30

agusta

It doesnt make sense to me the way this boiler is wired.
My opinion wound be.
a/the switched live should turn on the boiler and pump
b/The live feed through the pipe stat should also be wired to the pump also,similar to wiring a frost stat
c/When switched live is turned off,the pump will run with the live feed from the pipe stat.
d/This way if you set the pipe stat at 60 degrees, the pump will run for less and not cool down the heating system and still prevent the boiler from overheating
Any thoughts..

wilser

agusta wrote: »

It doesnt make sense to me the way this boiler is wired.
My opinion wound be.
a/the switched live should turn on the boiler and pump
b/The live feed through the pipe stat should also be wired to the pump also,similar to wiring a frost stat
c/When switched live is turned off,the pump will run with the live feed from the pipe stat.
d/This way if you set the pipe stat at 60 degrees, the pump will run for less and not cool down the heating system and still prevent the boiler from overheating
Any thoughts..

When C happens won't the boiler be still firing as its linked to the pump?
Think you have to have it set up with A or B but not both unless you use a relay

agusta

Yes Wilser you are correct on C,my mistake
How about this then,
Using pipe stat,
a/ connect the pump live to com
b/ connect the permanent live to no
c/connect switched live to nc

no = normally open.closed when hot
nc=normally closed.closed when cold

When pipe cold = feed is by switched live
when the pipe heats the pipe stat switches to the permanent live to feed the pump.
When the boiler is turned off [switched live],the pump feed is by the permanent live until the temperature drops.

wilser

What happens if you set the pipe stat to 50? If the pump starts when the pipe reaches 50 would that not work better as the rads won't be cooled too much?
Looks like you may be over complicating things

agusta

wilser wrote: »

What happens if you set the pipe stat to 50? If the pump starts when the pipe reaches 50 would that not work better as the rads won't be cooled too much?
Looks like you may be over complicating things

Simplified it...
if pipe stat set at 50 degrees, the switched live feed the pump until the pipe stat reaches 50 degrees