5 zone / two boiler linked CH system

[siroccomanuk]

Hi, a little help if possible please. Myself (electrical contractor) and a friend (plumber) have been asked to install a heating system which will have FIVE zones and two boilers. One boiler will be a normal oil fired, the other will be a wood burner unit to be used occasionally. The zones are split as follows:
1. Upstairs & dormers heating
2. Ground Floor
3. Hot water tank 1 (for main house)
4. Granny annexe (above garage)
5. Hot water tank 2 (for annexe)
The system will also have an 'open ring' for towel rails.

Now, how can this be configured so if the main programmer is off, the wood burner can be in use and heat all the zones and vice versa. I know there must be an easy option?

The system is to have one large pump for ALL zones etc?

Any help would be most appreciated

Dave

 

[mickyg]

Don't quite understand what your plan is here. It doesn't seem at all logical.
To operate a large system with multiple zones, your best option will usually be a Low Loss Header, with individual pumps. However if you are going to go for multiple fuel sources then you might be better off with a Thermal Store unit.

 

[siroccomanuk]

logical not at all - its the customers choice, and after all the customer is always right even when they are bloody wrong!

We were thinking of a Dunsley Baker neutraliser system, but have no experience with them, and although obviously safe, in the event of a power cut, how can you be sure that the solid fuel part of the system does not overheat the system

Any one used this system, if so any tips / hints etc would be greatly appreciated

D

 

[electronicsuk]

Can't give you an answer on the plumbing side of things, but electrically it might be worth installing a programmer for the HW tanks, and then individual timed thermostats in appropriate areas of the house for each heating zone. It would make sense for these all to run from the same supply, otherwise there is a risk that if one timer/stat is isolated for maintenance, the demand to the boiler at that stat may still become live should one of the other units call for heat. It's especially important when you consider that an electrician working on the installation could test and prove dead, only for one of the other stats to cause the installation to become live while he's working on it.

If they desire central control then you may want to take a look at the Heatmiser system. They produce a range of low voltage networked timer thermostats (and a central touchscreen control if you so desire) which are wired back to a central control unit, this contains a number of relays which then provide 230v to control your individual zone valves. It also removes any worries about multiple supplies, as the central wiring centre provides one set of volt free contacts for boiler demand that can be switched by any/all stats on the system. I can vouch for it as I have installed this system in my own house, and I have timed temperature control for each individual room.

Of course, that still leaves the issue of multiple boilers/burners. I wouldn't advise running the system such that the wood burner heats all zones, it makes a lot more sense to provide zone control regardless of what source you're generating the heat from. Besides, the wood burner might not even be man enough to heat the house + two hot water tanks. Suggest you come up with some solution as to interlock the two systems electrically so they cannot be used at the same time. Of course, not being a plumber, I'm automatically assuming it would be a bad idea for both to be on at once.

 

[cider]

you need to decide from the output of the stove what it is capable of heating and connect those zones to a neutraliser. thes zones need to have fail safe circuits which can gravitate in case of power failure esp if the stove has no water thermostat.
then run the boiler to the rest of the zones and into the neutraliser to take over from stove.
Not for the inexperienced to tackle as building regs need to be adhered to for the stove plumbing as well as some preety complicated wiring which as i said all has to be fail safe.

 

[Norcon]

What type of woodburner? Dedicated to water heating?
Im doing one at the moment which will possibly have a large waste woodburner/incinerator fitted at a later date to supplement the oil boiler.
This is all in situated the garage. A whopping thermal store will be fitted and some form of three port divertor on the primary flow with one port to a whopping plate heat exchanger.

 

[siroccomanuk]

Dual purpose. Water heating and for real fire in main lounge

 

[Biggles..]

Dunsleys are only suitable for open vented heating therefore your oil boiler will need to be open vented also.

Have done very similar locally but with 38kw gas/30kw wood and used a thermal store.

Am in the process of completing another on saturday which is 40Kw gas/ 60Kw waste oil and thats on a low loss.

the thermal store works brilliant and suits its need but so does the lowloss and unvented solution.

 

[Norcon]

Cue Bigburner and Oilman.
lol