Solid Fuel Hot Warter Questions,,,,,,Help Please.

[jrobb2000]

Hi Guys,

I am looking to supply my DHW via a Multi Fuel stove connected to some kind of thermal strore/tank.
The tank will sit 2.5m directly above the stove in the attic.

I have been on the phone to a number of companys who sell tanks but have had some conflicting answers so I am in the need of hearing your views (as I wont be buying a tank from you) of which tank I should be looking to buy. I am looking to have an extra coil for the installation of a solar loop at a later date.

Iam told I will need around a 170-200L tank. 2 bed house with 2 adults and one child.

With a 4-5KW (to water) stove outout.

Can you tell me what type of tank you reccomend?

Can I rely on gravity for flow and return to the boiler?

Do I need to have a heat leak radiator?

How much should this tank be costing me?

How long will the tank stay warm enough for if we are not using the water, what I mean bu that is that I work over night sometimes and I would like to be able to come home and have a shower without having to heat the water.

Shoud the mains water in (hot feed) be fitted with some sort of pressure reducing valve?

If you are anyhwhere near Biggar in Scotland and fancy coming around with your expert eyes then that would be great!!

Thanks for your help in advance,

JJ

 

[SimonG]

Post your requirements in the 'Looking for a plumber' forum, you need expert help and advice as it's a job for somebody with experience in this.

 

[ecowarm]

Thermal store sized @ 50l per Kw output to water is correct

So a 4Kw stove needs a 200l thermal store

 

[AWheating]

the thermal store needs to be sized to suit output demands, most manufactures will have guidence on sizing. The cylinder will need to be designed to be used with solid fuel, which means its rated for the temp(bs 1556 grade 1 i think) and the coil is designed for gravity circulation. Manufactures like Gledhill will make you a cylinder to whatever spec you want. It will also need a blending valve to keep temps down.

It will also require a temp relief valve and discharge pipework (d1 and d2) fitted to part g of the building regs, any f+e tanks will need to be metal or fibreglass rated for 110*c and the overflow/s to be copper.

if your thermal store is size to atleast 50ltrs to every kw of output from the appliance you do not need a heat leak radiator but i would personally still fit one especially if you have other heat sources to the cylinder sized at atleast 10% of boiler output.

most cylinders are rated at 0.8*c per hour heat loss i think( but the cylinder manufacture can give you there own figures), so if you dont use any hot water and its all lagged up you should be good for hot water for a while.

pipework must be = 28mm primary flow and return,only bends not elbows. Heat link if fitted must be 22mm to last 300mm to rad and be flow on the top of the rad and return on the bottom.

The system must be signed off by a hetas registered engineer or build control, so its best to get a qualified hetas engineer in to fit the system and you should get a safe installation. if you go to the hetas website you can get link to installers in your area.

also check if your area is smokeless, if so you can only install an approved appliance.

i hope ive helped.
Multi fuel thermal store cylinder. Combine heat sources including back boiler, solar, gas or oil boiler.

 

[Nostrum]

200 litres will take about 14kwh's to heat from 10 - 70 oC so presuming you get minimum heat loss and don't draw anything off whilst it's being heated, your 4kw stove will take approx 4hrs to heat the store from cold.

I think thats right but i've had a hell of a day so might want someone to confirm!

As for how long the tank stays warm for, that info should be supplied by the supplier. They will tell you in kw/24hr.