Which heatbank?

Hi All,

Ok so we are going to go for a heatbank type hot water system. Ive found the Pandora systems online, they sound professional. Has anybody any other recommendations for manufacturers that are worth investigating?

Thanks, Matthew

Reply to
Matthew
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Gledhill also do them.

They also do one box solutions with the boiler built in, which means you can run the heating at low temp, whilst heating the store to high temp.

Christian.

Reply to
Christian McArdle

You can do that with the pandora - the heating can run through a plate heat exchanger and a thermostatic mixer, so the heating system temperature is only heated to the set level.

A
Reply to
auctions

But the boiler would still be running at a high temp so not operating at max. efficiency (I presume that is the difference)

Reply to
PeTe33

But that doesn't provide the best efficiency from the boiler, although it would improve things, as the return temp would still be lower.

Christian.

Reply to
Christian McArdle

I have an Albion Mainsflow which works superbly. It's much cheaper than the equivalent Pandora as it uses an internal coil to heat the DHW rather than an external plate heat exchanger and pump. It cost me about =A3650 (for a 140 litre direct, cased version). DPS quoted me over a grand (from memory) for the Pandora.

-Antony

Reply to
Antony

Hi Antony,

I had a look at the Albion website and then phoned them up. It sounds as though this may be our preferred option. The Pandora system from DPS is a lot more expensive along with the mains system from Gledhill. The nice thing about the Albion unit is that it will retrofit straight into our current Honeywell Y plan system without too much fuss. Were did you buy the Mainsflow from and did you get any discount?

Although I could fit it myself I will probably get a plumber to fit it for speed. Maybe a days work?

We have 3 bathrooms with the potential to have 3 showers in use at once. Initially I was thinking of buying 3 booster pumps which for decent pumps works out to about

400 to 500. It is probably better to pay a bit more and go for a high pressure cylinder. I did think about the megaflow option but I have been put off those for a number of reasons (servicing, hard water etc).

I have to check our mains pressure and flow rate before I progress. If there is a problem with that then I suppose its game off unfortunately.

Thanks for any advice, Matthew

Reply to
Matthew

Matthew, I bought it from

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(though it was delivered by my local Plumb Center, so I guess they just have an account). Checking their site, it looks like the price has gone up a fair bit over the last 12 months (higher copper prices?). My model is an "MFT25/140 Direct Cased Contractor", but from your description it looks like you want an Indirect model. There are other suppliers, so check around for the best price (I Googled, and one came up on eBay).
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looked cheaper, and they probably just use Plumb Center like most internet-based plumbing sites.

Finding a plumber who is familiar with these types of systems could be difficult. I installed mine myself. It was certainly more than a days work, but then I completely replaced my entire CH/DHW system (the thermal store sits in the loft above the airing cupboard on the "raft" that used to support the 50 gallon water tank).

As you're moving from stored water to mains pressure, I'm sure you'll need to do some fairly extensive replumbing to get a 22mm mains water feed to the store. Also the store comes with a pressure reducing valve, preset to 3.5bar that needs to be fitted somewhere upstream of the unit to protect it.

You mention having hard water as a reason not to go unvented. Actually, due to the higher temperature in a thermal store, and the heat exchanger coil (4 long 10mm copper coils in the Albion) it is more prone to scaling than an unvented cylinder. I live in a hard water area, but I'd already installed a water softener (a Monarch "Midi") prior to getting the thermal store. One reason for going for an external heat exchanger (e.g. Pandora) is so you can remove it for periodic descaling. I'd highly recommend getting a water softener whatever your decision as it's so much nicer.

As far as water flow goes if you want to run 3 showers at once you want around 30 litres/minute. The static pressure needs to be decent - the usual test is to hold your thumb over the kitchen tap - if you can stop the flow the pressure is too low.

-Antony

Reply to
Antony

Also McDonald engineering do coil-in-cylinder (rather than external plate heat exchanger + pump) types. If you have an open rather than sealed primary system then you can get very good recovery rates and lower temperature drops between primary and DHW (and thus better efficiency from a condensing boiler) by having a thermal store in which the stored water is part of the boiler primary circuit. McDonald seem quite keen on this arrangement.

Reply to
John Stumbles

Fit a Magnaclean filter on the CH return to the thermal store.

Reply to
Doctor Drivel

Best have DHW priority system. The boiler set to max and when CH is called DHW switched out when up to temp, and then the boiler temp is floated in line with the outside temperature by a weather compensator. The Danfoss model is quite cheap.

Reply to
Doctor Drivel

I think he means take the CH water via the plate which is heated from the hot water in the cylinder.

Reply to
Doctor Drivel

Hi Antony,

I had a look at the Albion website and then phoned them up. It sounds as though this may be our preferred option. The Pandora system from DPS is a lot more expensive along with the mains system from Gledhill. The nice thing about the Albion unit is that it will retrofit straight into our current Honeywell Y plan system without too much fuss. Were did you buy the Mainsflow from and did you get any discount?

Although I could fit it myself I will probably get a plumber to fit it for speed. Maybe a days work?

We have 3 bathrooms with the potential to have 3 showers in use at once. Initially I was thinking of buying 3 booster pumps which for decent pumps works out to about

400 to 500. It is probably better to pay a bit more and go for a high pressure cylinder. I did think about the megaflow option but I have been put off those for a number of reasons (servicing, hard water etc).

I have to check our mains pressure and flow rate before I progress. If there is a problem with that then I suppose its game off unfortunately.

Thanks for any advice, Matthew

Reply to
Doctor Drivel

Thanks for all the useful info as ever. At least Im now primed for when I talk to a plumber. The Albion Mainsflow looks to be the favourite option due to cost. The info on the accumulator is useful to know if we did have future problems. I would probably fit that myself. BTW how much does something like that cost?

The only issue to be resolved at the moment is placement.... Obviously it could replace the existing cylinder in the airing cupboard. The pipework would be very straightforward. Potentially, it could also go in the loft in place of the existing gravity feed header tank with a little bit more pipework. This would free up a large cupboard to give us extra storage space upstairs. I presume the small CH header tank would need to be lifted above the new cylinder on a small platform? Has anybody any advice on the pros and cons here.

In terms of the incoming mains feed, it is reduced down to 15mm in the kitchen. I think this could all be replaced with

22mm when we do put in a new kitchen. For the near future we would make do with the existing 15mm feed for ease. Thanks, Matthew
Reply to
Matthew

Cut from Google>>>>

The Reliance 200L accumulator is ~£300.

No. 2.

So the controls and all can be fitted for a fraction of the price of the Dual Stream (link below). About £400 inc controls for a 200 litre which effectively will store about 100 litres of cold water, which is fine for a one bathroom house. It gives the static mains pressure but lots of volume. If the mains is cut off there is a store of cold water.

I would say minimum 1 bar mains pressure to operate and a pressure relief valve.

You need on the mains pipe.

- A double check valve on the mains pressure reducing valve set to what Reliance recommend (maybe around 3 to 3.5 bar). They tend to specify a pressure reducer, in case the mains spikes and ruins the accumulator diaphragm.

- line strainer

- Full bore maintap

- Pressure relief valve set above the PRV (if a PRV needed)

- tundish

If using a heat bank then that will be OK. If the cold is supplying a volume of water that will be heated (unvented cylinder), then a double check valve on the cylinder supply.

Some Reliance accumulator models may have the diaphragms replaced too. Look at this to give an idea of where components fit:

gravity feed header tank with a little bit more

The header is incorporated within the Albion cylinder (they have with and without models). Look at the Range FlowMax thermal store/heat bank with a plate heat exchanger and usually well priced.

In any mains pressure system, have a 22mm dedicated line to the cylinder direct from a full bore stoptap. No tee-offs from this line, except the cold to the showers which should be teed off just before the cylinder. A separate 15mm line for each shower

Reply to
Doctor Drivel

As I said before, in my case I installed a Direct version of the Mainsflow in the loft directly above the airing cupboard (I installed the boiler is in the airing cupboard). With this model it *is* the feed & expansion tank for the system. There's a ballcock at the top of the cylinder to fill it (just like in a F&E tank). If you use the airing cupboard to dry clothes, then you'll need to include a very small radiator (or some exposed pipework) to replace the heat that would have come from the cylinder.

Note that you need to think about how you'd get the store into the loft

- is your hatch big enough? I'd wanted to replace my tiny hatch with a larger combined hatch/ladder, so did that at the same time - I rigged up a simple pulley system to haul the store up (with a lot of help from my Dad).

The water in the store is the Primary water and there are two pumps/connections - one pumps water to the boiler (I used a standard Grundfos Selectric fixed speed type) under the control of the boiler. The boiler is controlled (i.e. "call for heat") by the programmer+cylinder thermostat.

The second pump supplies the radiators (I used a Grundfos Alpha self-modulating type for this) and is controlled by the programmer+room thermostat. This eliminates the need for zone/diverter valves. The instructions with the store tell you how to set up the wiring, which is very simple.

You are looking at some quite significant work here to make all these plumbing, electrical (and carpentry for that matter) changes, but you should be very pleased with the end result.

-Antony

Reply to
Antony

How does the Alpha perform? Have you TRVs on all rads?

Reply to
Doctor Drivel

It seems to work as intended. You can hear it changing speed, and I don't have any problems with hammering pipes or whistling TRVs, etc. I have TRVs on all the upstairs rads plus the hallway. The rest of the downstairs is open plan and I have a Honeywell CM67RF in the lounge, so no TRVs there.

-Antony

Reply to
Antony

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