Help!

wrightk

muckybutt wrote: »

4 pipes means you will have a flow and return for CH and another flow and return for HW.

I can honestly say ive never seen a pump fitted onto the Return side as obviously its the cooler side, as far as I am aware the pump should always be on the Flow side as should the stat.

Have you got a heat dump rad ? ie one that has no thermostatic valves on, normally the biggest rad closest and above the stove. I cant see the need for two stats tbh when one works just as well, fair enough if one fails the other will kick in butby that time the heat dump rad will be dissipating the heat quite merrily so as not to burger the stove.

I have a heat dump rad. 4 of them! and only 2 work because from what ive heard thats way too many on gravity. only downstairs is pumped oddly. Both the return and high limit stat are wired into the pump via a charnwood control unit. The return kicks in the pump initially when the return pipe reaches a certain level. The high limit stat which is on the hottest pipe that goes into the cylinder is never used but i presume its only there in the event of the previous failing and will kick in when the flow reaches 75c

edit; space is an issue for putting both stats on the flow as the pipe bends downwards

wrightk

one of the rads upstairs has no trv's on (bathroom) its a fairly small rad to be honest. the rest do but i presume if their gravity rads they shouldn't have and that was a mistake by whoever put them in.

Ive followed the pipework from the pump and none of it actually goes upstairs

Greenfires

Interesting thread! friends have a wood fired range cooker which does the hot water as well. They had big problems to start with as the water wasn't getting hot and the fire was not very lively. Mate of mine a hundred miles away said it would be the setting on the return stat being set too low - meaning that cool water was being circulated constantly through the stove - which would also take a lot of heat out of the firebox. Anyway - they turned the return stat up by five degrees and it completely transformed the job.

Canucklehead

[FONT=&quot]Taken from the Charnwood Cove 2B manual.

[/FONT]

[FONT="]
W[/FONT][FONT="]e recommend fitting a pipe thermostat onto the gravity return to act as a low limit thermostat This should be wired into the mains supply to the pump so that if the gravity return temperature drops below 45º C then the pump will cut out. This will help to prevent condensation forming on the boiler faces and will thereby increase the life of the boiler. It will also ensure that priority is given to the domestic hot water. [/FONT]

As the manufacturers have taken the time and trouble to have their appliance tested and certified to produce heat and hot water to it's optimum, I don't think moving the stats around will improve anything.


The Broseley Hercules has the almost the same requirement (page 3 of 8 installation and use) except the low limit stat can be fitted the the cylinder as an alternative.

Always read the installation instructions for the appliance rather than generic (and possibly incorrect) advice over the internet.

SEE

Canucklehead wrote: »

[FONT=&quot]Taken from the Charnwood Cove 2B manual.

[/FONT]As the manufacturers have taken the time and trouble to have their appliance tested and certified to produce heat and hot water to it's optimum, I don't think moving the stats around will improve anything.


The Broseley Hercules has the almost the same requirement (page 3 of 8 installation and use) except the low limit stat can be fitted the the cylinder as an alternative.

Always read the installation instructions for the appliance rather than generic (and possibly incorrect) advice over the internet.

I'm confused about what difference it makes so long as your pump isn't set to run on cool?

muckybutt

SEE wrote: »

I'm confused about what difference it makes so long as your pump isn't set to run on cool?

My stove is a Charnwood Cove 2, been in nearly two years now with the set up still as was done by the plumber back then, sure every manufacturer will have "their way" of doing things, personally I'd rather go on what an experienced professionalplumber would recommend.

Take the small 15mm loop my plumber fitted, basically to help heat the stove up quicker, some of the flow side is diverted back into the boiler thus warming it up quicker and keeping it warm and it also helps in the long run as the tar / creosote build up as is very common with boiler stoves is considerably less, now non of that is mentioned anywhere in Charnwood's install advice or any one else's that I know of.

Canucklehead

SEE wrote: »

I'm confused about what difference it makes so long as your pump isn't set to run on cool?

I'm confused about what you are confused about!

SEE

Canucklehead wrote: »

I'm confused about what you are confused about!

If the stat is on 55 on the return, it has waited for the tank to fill to temp before switching on the pump.

If the stat is on 55 and fitted to stove outlet it will turn the pump on faster, but ultimately its still running at 55 around the whole system and switching off when it drops below?

My confusion was the poster saying cool water in my stove boiler would !!!!!! it up, but the water would never be cool if set at 55?

wrightk

just thought id post a little update. had another heating engineer around today who actually seemed to understand solid fuel heating systems! woo.

apparantly i need a repipe around the hot water cylinder. whoever plumbed it in has used a standard pipe width (rad size) on the return pipe of the hot water cylinder as opposed to the thick pipes that come from the stove. this is starving the system and the return pipe of heat and it is in an odd loop and needs to be cut off and joined in back to the pipes that run to the stove

SEE

Problems here too. Son went up the attic today and there is nothing on the tank which would indicate a switch of any form to decide water/rads etc. Stove is melting hot, as are radiators, but hot water tap is running freezing cold.