boiler size

[AWheating]

You are allowed a zone valve, but it has to be normally open as I mentioned, so if the power drops out it springs open. The laddomat 21 also has a bypass when switched off allows gravity circulation on power fail.

I have fitted several Gledhill thermal stores. One problem you get is the central heating return isn't baffled and mixes up the tank, destroying the stratification of the store and your hot water section, some thermal stores use a baffle plate running height of the store too avoid mixing. I always pump away from the store and set the pump speed low, ideally a return layering/blending valve would fix this on the Gledhill, only allowing 55 degree water back to the store on heating warm up.

you are allowed to fit a normally open valve on the gravity to a cylinder which would be normally controlled by a cylinder stat as required by part l but you are not allowed to fit one on the heat leak radiator pipework.

 

[alexmurchison]

think i will just install the oil boiler and therm store, leave the pipework and solid fuel part to the hetas guy, he can do what he wants and sign it off saying he has done it !! Does the torrent have a built in stat or is it something seperate i need to get,

 

[blakeecotec]

Well the thermal store manufacturer has to amend his drawings, so will APHC, the H2 panel and HDG Euroheat diagrams will not be allowed to be used either as they all show use of normally open 2 port valves used in the flow to a heat leak radiator.
The Solid Fuel Association state:There must be scope for the dissipation of heat from the appliance in the event of a pump or power failure. A heat leak radiator should be provided sized to the turn- down output of the appliance (usually 25% of maximum output). The stove primary pipework should always be designed so that in the event of a pump failure, heat can circulate by gravity (thermosiphon) to the store or to the heat leak radiator. Where the primaries are pumped, a bypass should be fitted to the pump to facilitate an unrestricted cold feed to the appliance (10mm diameter).

 

[AWheating]

if manufacture instructions show it then i assume it would be ok as its been tested to be suitable, but in general on a gravity solid fuel system you cant fit anything on the heat leak pipework.

Hetas states that "it is essential that a heat leak radiator is capable of dissipating heat at all times" so it must always be able to have a flow of water through it at all times. Having a motorised valve fitted would mean at certain operating times a flow of water would not be available through the heat leak radiator.

if you fit to MI your covered, i have not seen any manufactures diagrams that show a motorised valve fitted to the heat leak pipework so i cant comment on specific manufactures designs.