Heat pump / inverter DIY

stevehead

Latlum wrote: »

Wow they sound fantastic.:T

I'm looking for a solution to heat a flat created for my daughter above our garage, plus seperate games room for the rest of the children downstairs (back of garage). I'm looking for the most economical (to run).
We have oil and calor gas already both supplying our hose and they are so expensive!
Can anyone help?
Would these Mitsubushi Units do the trick? Do heating, heat the water in the flat AND cool the place in the summer ??
:question:

I woud suggest a gas multipoint for your hot water needs, and a gas cooker. The cost of running these services alone is pretty negligible - we (family of 4) spend approx £4 per week on gas for these.
The Mitsubishi's will cater for your heating very cheaply, and cool in the summer if you must.

paceinternet

As anthonykeates says, you need to check out air to water heat pumps for those requirements as they will give you low running costs. A big range of purchase prices as they are relatively new technology. Having oil or lpg as a secondary support to your system will be a nice backup.

Hermann

Latlum wrote: »

Wow they sound fantastic.:T

I'm looking for a solution to heat a flat created for my daughter above our garage, plus seperate games room for the rest of the children downstairs (back of garage). I'm looking for the most economical (to run).
We have oil and calor gas already both supplying our hose and they are so expensive!
Can anyone help?
Would these Mitsubushi Units do the trick? Do heating, heat the water in the flat AND cool the place in the summer ??
:question:

If its a recent conversion then hopefully there is good insulation and draughtproofing, if not then insulate and seal the draughts first.

If your choice is limited to oil, calor gas or electric then it could be that a heat pump is a sound bet. Easier installation than oil or gas and much lower maintenance costs.

If its only space heating you need then consider an Air to Air Heat Pump, this will heat when you're cold and cool when you're hot.

If you need Domestic Hot Water then you'd probably be best to extend your existing house DHW to the garage.
Alternatively a gas multipoint point may be useful however running on calor gas will be a lot more expensive then steves mains gas one! It will also have to be a Corgi only install and maintain which is likey to be expensive.

If the situation calls for a complete new intallation of boiler system with radiators and running water then Air to Water Heat Pumps could be considered. They seem to vary a lot in price and installation costs also seem to vary a lot.

Out of interest a heat pump such as this ......
http://cgi.ebay.co.uk/AIR-SOURCE-HEAT-PUMP-OIL-GAS-BOILER-REPLACEMENT-11-9KW_W0QQitemZ270329568119QQcmdZViewItemQQptZUK_Home_Garden_Hearing_Cooling_Air?hash=item270329568119&_trksid=p3286.c0.m14&_trkparms=72%3A1296|66%3A2|65%3A12|39%3A1|240%3A1318 ( not recommending it! just using it as an example)

is self contained and simply provides a water flow and return to be connected to the rest of your system. This means that the rest of the plumbing, radiators etc, are all standard plumbing easily carried out by any competant person.

You haven't said where in the country you live but give consideration to how much of your winter is sub zero if you are going down the heat pump route. If you spend the winter covered in snow at -10 then an air sourced heat pump isn't such a good idea.

Sounds like using your existing house DHW and a ASHP or two is well worth considering, especially if you take installation and ongoing maintanence into account.

If you're reading discussions comparing Gas Heating to Heat Pumps check if its mains gas or LPG being compared as there's an enormous difference in costs!

housesitter

craigix wrote: »

I found a plumber who let me hire his vac pump from him.

What sort of thing are we looking at ?
What level of vacum do you need to achieve ?

See, I'm wondering if you can "knock something up" to do the job. eg: Air compressor with vac attachment, using a car's vacum system to suck out the pipes, and so on.

yes I am Heath Robinson.

Hermann

It would be interesting to know more about what craig used.

In the meantime pages 22 + 23 of this manual may give you some idea of whats needed .......
http://uksupply.org.uk/cond/installation.pdf

Specs and pressures differ from manufacturer to manufacturer.

R410A refrigerant systems run at a higher pressure so ideally I think they need a high pressure leak test, which is where the nitrogen injection comes in and this I suspect is difficult for DIYers . Getting hold of bottled Nitrogen is going to be a problem.



It sounds like Craig didn't use nitrogen and relied on the vacuum test to highlight any leaks, perhaps he could confirm?

Whilst I can see this may work in practice technically testing under vacuum isn't the same as testing under high pressures, seals that hold a vacuum may fail under pressure.

richardc1983

it isnt law u have to use nitrogen to flush it out. My inistaller just used vac pump to remove all air, whilst he was putting system in he ensure the ends of the pipe were covered over with tape.

housesitter

Hermann: I'm beginning to think that the best bet for doing this might be a mobile car air con guy. A guy I know on/off (tho other side of the country) does A/C regassing and system evacuation plus leak testing for cars.
perhaps worth a call to one of them?
They generally use a different gas (R-134a instead of R-410A quoted in your manual), but I'd figure it's similar proceedure wise ?
I wonder why the different gas too ?

Latlum

Thanks for your suggestions

Am still undecided and a plumber is arriving on Saturday to have a look at what needs doing (basically to install heating, running water & fit an ensuite & kitchen plumbing). He's expecting to either link up to our house (calor gas & existing boiler) or to an oil tank (via new boiler) (this is his preferred route) The oil supply at the moment heats (very expensively) our swimming pool.

We live in Kent which is supposed to be warmish but we've just had a week of -10 each night.

The builder is starting on Monday to do the conversion (putting in the insulation). The good news is it will be well insulated but bad news is I reckon it will be VERY hot, probably unbearable up there in the summer.. 4 velux windows all south facing. So I should think about an air/air heat pump to do the heating and the cooling.

But then from what you're saying I'll also need to add an air/water pump for the water or alternatively link the flat to the oil tank (purchase a boiler for the purpose) or link to the house DHW (powered by Calor). BTW the oil tank is v close to the flat, the house is a bit of a distance away (25 feet), so running the pipes across I guess will be costly.

Either way looks like I'll need almost 2 installations? (Seems a lot of expense/ complication for a 25ft x 10ft flat plus games room half the size below) ?

Am I barking up the wrong tree with these pumps and should I just go along with the plumber's suggestion of linking it all up to oil and telling her to use it sparingly, put on an extra pair of socks?

But if we switched the swimming pool (which I know we won't be able to afford to heat this yr) away from the oil to an air/heat pump we could get rid of the ugly oil tank. Maybe use the same air heat pump for the flat? Except the pool is about 40 feet away from the flat.

Am in a muddled state.

thechippy

housesitter wrote: »

What sort of thing are we looking at ?
What level of vacum do you need to achieve ?

See, I'm wondering if you can "knock something up" to do the job. eg: Air compressor with vac attachment, using a car's vacum system to suck out the pipes, and so on.

yes I am Heath Robinson.

You can't really make something, you need a proper vac pump. Ideally should should pull the system down to a 30" vacuum.

Craig, why would your plumber have a vac pump? they have no use in plumbing.

Hermann

Latlum wrote: »

Thanks for your suggestions

Am still undecided .......................

For what its worth my thoughts are the following ....

Don't install a new oil boiler for the flat.

If you had the time to research and plan then seriously consider an air to water heat pump to run a wet install in the flat and heat the pool when needed. would need a boost for DHW though, most likely an electric immersion.

Failing that, and ignoring the pool, use air to air heat pump to space heat flat.
For running hot water it really depends on usage. It sounds like it will be a case of occasional shower plus hand/kitchen washing up for one person (or 2?). If thats the case an electric shower and 'instant water heater' for taps may be the solution. The whole lot heat pump, shower and heater would be less than a day to install so should be a cheap installation.

I guess you'd need quotes to be sure but I'd guess the Heat Pump/instant water heater /shower could be around the £1500 - £2000 mark. An oil boiler with rads and DHW could easily be £3000 - £5000. The oil run DHW may be slightly cheaper to run than the electric instants BUT with such low usage I doubt you ever save enough make it worth the extra install costs. The money you'd save running the heating as heat pump would probably far outweigh the 'expensive' hot running water.

If you anticipate very high hot water demand the costing may work differently.

If I was doing this in Kent I'd take the gamble that outside Temps will be fine for an ASHP. In the past 10 years how often have outside temps been under -5 all day? I suspect very rarely if ever. People like stevehead are in a better position to comment on this as he has an ASHP already installed and is on the south coast so should be similar climate and has run ASHP through the very cold snap you refer too.

To summarise and ignoring the pool (although you probably should include the pool) from what you seem to have described I'd be fitting an ASHP to space heat/cool, an electric shower and instant water heater. (then insist daughter uses hot water sparingly ). Quick low cost install, low cost maintanence, low running cost heating, high running cost DHW (but your alternative of oil or calor gas are also high running cost DHW with much higher install/maintanence costs).
I'd also be fiiting decent blinds to those Velux windows. Gotta keep the heat in when its cold and sun out when its shining.

One final thought to confuse you even more, if you did decide to have a boiler for the DHW then you could lower its running costs by including some simple solar panels, even home made ones work ok. You have that south facing roof after all.

Personally the high install cost of boiler/solar would put me off in this case but if you do have a boiler nows the time to make sure you get the right water tank (or thermal store!) installed to allow for solar even if you fit the solar later.

All just my thoughts and personal opinion others may well think differently! There could also be something about your site/install that negates all this but from what you've said I doubt it.

Good Luck :beer: