Using a SLME as a low loss header.

[AMEdinburgh]

I have purchased a 400L SLME to go in my extensions to provide

1) intermittent large volumes of hot water and a recirculating DHW loop for regular hot water draws.

2) Connection to solar via the bottom coil when money and time permit.

3) To supply heat to the CH loop in the original house (currently being fed from a combi which is to be removed when a new primary boiler is installed)

4) To supply heat to the CH loop in the new extension space

5) To supply heat for a small heat exchanger for a therapy pool.

6) Possibly to supply a CH loop in a modest tied flat to be constructed in the roof space.

My question is:

Is there any reason why each of 3) 4) 5) & 6) could not be considered separate circuits each having a pump, programmable timer and a thermostat?

This would make the installation and fault finding fairly straightforward.

All helpful comments gratefully received.

 

[AMEdinburgh]

Anyone out there with a helpful suggestion?

 

[compheat]

you can use individual pumps, they will all have to be balanced and non return valves installed, it could cost more.

 

[looneyfitter]

By 400l slme are you refering to a twin/single coil vented/unvented cylinder?

If so you could achieve the same by using your combi instead of swapping it, but use the hot water draw from the unit for off peak hot water delivery to kitchen taps etc.

Yes you could also very easily zone and programme the other zones fairly straight forwardly.

Check out heatmisers website. They have a fantastic range of controls which can also be programmed from a remote P.C should you require.

 

[Biggles..]

due to the varying loads your describing im surprised that your heating eng hasnt done a specification for you.

what are you going to do with each circuit,are they to be the same temp,variable temp.how do you expect to control each pump.how are you intending to regulate the flow of each circuit.What pool exchanger do you propose and will it be 3 port mixing or 4 port.

reality would be a LLH with individual load pumps,mixing valves if required,DRVs for balance.BMS based controls.trouble will be finding someone who knows how to fit it and make it work.

downside: all that comes at a cost,when single pump and multiple zone valves (typical installers ideas) will do the same thing ish.

 

[looneyfitter]

Heatmiser controls will control the variable temp and constant temp circuits no problem at all. You can also get very simple pool climate controlers without complicating things. I would stick with 3 port mixing personally.

I assumed he was going to use the vessel as a Low loss header.

Double reg valves would be ideal but costly. As said it all depends how much you want to spend.

 

[AMEdinburgh]

Thank you, compheat.

I was thinking of using something like the Grundfos Alpha2 as each pump. Can you explain the basics of balancing for a non plumber and by a non return valve do you mean a single check valve or something else?

Thank you looneyfitter.

The SLME is a tank in tank cylinder with a lower coil for solar and the primary circuit from the boiler is 219 litres the DHW being 164 litres.

My combi is a 1995 vintage Worcester 350 and is coming towards the end of its life so the plan is to swap to a new larger boiler in a new location which will then hopefully be reliable. I plan to add solar when money and time permits.

I'll have a look at the heatmisers website

Do double reg valves have an "official" name, to enable me to educate myself.

Thank you lcgs

I don't yet have a heating engineer. Due to financial constraints, the boiler is not yet at the top of the list on my slowly progressing project but I do need to plumb the SLME and set up the zones, so I can put the floor down. I have done some research and posted here and am drawn to the Atag range for compact size and good quality. I want and really need to understand how it all hangs together and have the knowledge to repair the system so that any down time is minimised. If I put it in, I'll be able to repair it.

I was going to run each zone from the primary capacity in the SLME and the rads in each room have TRVs except for a central rad and wall thermostat in the original part of the building. I was thinking of using a Grundfos alpha2 on each circuit and a 7 day timer as the heating requirements in the original and new extension would be different.

The pool heat exchanger is a 30,000 to 50,000 BTU Bowman model and has 15mm capacity for the heating circuit. I was going to alter the pool plant to include it in series with the existing electric heater in the recirculating filter loop and install a thermostat pocket in the alteration. Hopefully then, the stat would call for heat and switch on the pump in that circuit and then go off when the pool is heated to temp. I might have this heating available all the time or just at night. I am weighing up the merits and technicalities of this.

 

[Biggles..]

Heatmiser controls will control the variable temp and constant temp circuits no problem at all. You can also get very simple pool climate controlers without complicating things. I would stick with 3 port mixing personally.

I assumed he was going to use the vessel as a Low loss header.

Double reg valves would be ideal but costly. As said it all depends how much you want to spend.

sorry your correct i didnt fully read the title.

Balancing would be done normally thorugh a DRV double reg valve.Have a look at hattersley,crane,oventrop for info.

 

[looneyfitter]

I dont know an aweful lot about tank in tank technology, however i do know a fair bit about thermal store. What i would like to ask tho is how does the unit provide HW control? I am assuming it is through a blender?

As said you effectively already have a low loss header, however i wouldnt be happy supplying all your requirements via 1 x 3/4 flow and return connection. It simply wont flow enough. In my opinion you will also have to fabricate another balanced header pumped from your SLME and then feed off from there via either dedicated constant temp or variable circuits.

It all depends what you will be feeding in the property. Do a search for double reg valves. They are basically just balancing valves which to be honest should also be fitted with binda test points. A little over kill but would set your system up considerably better

HTH Gareth

 

[Agile]

Be aware that he is a Scottish vet who likes to do all his own plumbing.

He has all sorts of spas for dogs, dog swiming pools, dog jacusis and about everything else that you could ever charge a dog for!

Tony

 

[AMEdinburgh]

Rest assured, Tony, I am going to have the boiler professionally installed in it's entirety but want to set the rest up myself. We only have a pool and an underwater treadmill!

I am currently digesting and researching the earlier comments. Would you have anything to add, as you've been most helpful in the past.

 

[Norcon]

Try ACV technical and see what they say.
With solid fuel and a primary boiler they recommend 1 and 2 (lower 2) for the primary boiler and 5 and 6 for the solid fuel.

I would connect the primary boiler in your case to 1 and 2.
Then the coil later for the solar energy. Some solar controllers can control a diverting valve between 1-2 and 2 afaik.

The central heating and separate heat exchanger for the therapy pool supplied from conventional set up. (ie- two port zone valves) and a single primary circulator.

That allows the solar controller later on to do its stuff independently of any interactions from CH flow through the lower section of the store.
It says on their sales brochure the cylinder can be used as a low loss header.
But whats the benefit?
I could be wrong but I only see problems arising when a solar controller is hooked up to the cylinder and the cylinder is constantly being charged to facilitate supplying independant zones through a primary/secondary set up using the lower section of a thermal store.
I doubt if the ACV 400 has enough ports to do what you are proposing.

 

[AMEdinburgh]

Thank you to everyone so far. I've sent an email to ACV and shal report what they say.