Cheap hot water system

[J1mbo]

Here, most significantly an annual service requirement by the look of it. But, does that annual service requirement exist in the scenario that there is no resistive heater and only an R290 ASHP? I can’t see what risk there would be.

[PeterW]

1 hour ago, SteamyTea said:

This problem can be tackled another way: looking at components needed.

 

So a simple vented system has a cylinder, an immersion heater (or 2), a feed and expansion tank, a ballcock valve, couple of isolator valves.

 

What does a unvented system have?

Issue with a single storey vented system (like for @Jilly ) is the water pressure is determined by the height of the header tank above the cylinder. And this will be low ..! UVC gives mains hot water with no tanks, a combined thermal store can do similar but needs higher temperatures to store the water. 

[SteamyTea]

9 minutes ago, J1mbo said:

Here, most significantly an annual service requirement by the look of it. But, does that annual service requirement exist in the scenario that there is no resistive heater and only an R290 ASHP? I can’t see what risk there would be.

I think even water at 97°C can do some damage.

Even at 70°C it can kill you.

[SteamyTea]

1 minute ago, PeterW said:

Issue with a single storey vented system (like for @Jilly ) is the water pressure is determined by the height of the header tank above the cylinder. And this will be low ..! UVC gives mains hot water with no tanks, a combined thermal store can do similar but needs higher temperatures to store the water. 

Does it need an expansion vessel?

 

Agree that UVC are useful for limited flow showers. But probably not cheaper than vented and a 100 quid pump.

[ProDave]

2 hours ago, PeterW said:

Drain all the hot water from the tank until it’s cold. Start up the heating system and check the temperature cut out operates correctly. 

That's an interesting one.  With a large tank and a low power ASHP that could take 2 hours, I don't want to be paying a plumber 2 hours labour to sit and wait.

 

That is something I can check myself just by watching it as it heats up on any day and ensuring it does turn off at the set temperature. And something I would expect a friendly plumber to accept I have self tested.

[Thedreamer]

2 hours ago, SteamyTea said:

No one commented on my ECOCENT (but find a cheaper version) solution.  I know the newer ones can take heat from outside now, so one down side of them has gone.

 

They are not popular here because of the quality of the cylinder.

 

I have a joule aero with a good cylinder and it works a treat. 

 

I have heard comments before like they come from China, yes some do.

 

If you watch the video, I am pretty sure this is Ireland or the UK! I also live in a soft water area.

 

https://jouleuk.co.uk/complete-renewable-heating-solutions/

 

Mine takes the exhaust air from the inside and I've not felt any change to internal temperature. I know the science would probably suggest a lost of energy, but none felt! 

 

If we have the occasion bath etc I can leave the hot water in and it sucks it back into the systems. External air source heat pumps can't recycle heat like that.

 

It can be geared to take from the outside as well.

 

I think there was a scandal before with exhaust air source heat pump as they were installed in some old properties but in a new self build they work well.

 

I have never used the dual immersion heaters in the cylinder and have no plans to!

 

My total electricity usage for the house is around £1.75 per day.  

[J1mbo]

33 minutes ago, SteamyTea said:

I think even water at 97°C can do some damage.

Even at 70°C it can kill you.

 

But there is no explosion risk because the stored water cannot boil. That is the reason for the annual services for unvented.

Edited November 18, 2020 by J1mbo

[PeterW]

44 minutes ago, SteamyTea said:

Does it need an expansion vessel?

 

Agree that UVC are useful for limited flow showers. But probably not cheaper than vented and a 100 quid pump.

Thermal store needs nothing if you get the combined one and ensure any heat emitter is below the top level of the header on a combined store. 
 

Newark Copper will make them to any size requested with any trappings and coils - ideal for a custom installation such as this. Downside is they do need to be kept hot - 70c is normal - so you are better ensuring there is additional insulation on them. 

[SteamyTea]

37 minutes ago, Thedreamer said:

They are not popular here because of the quality of the cylinder.

Is that an easy thing to check out?

 

Seems you are pretty pleased with yours.

 

16 minutes ago, J1mbo said:

 

But there is no explosion risk because the stored water cannot boil. That is the reason for the annual services for unvented.

Yes.

 

1 minute ago, PeterW said:

Thermal store needs nothing if you get the combined one and ensure any heat emitter is below the top level of the header on a combined store. 

You can also get a combined vented.

[SteamyTea]

8 minutes ago, PeterW said:

Newark Copper will make them to any size requested with any trappings and coils - ideal for a custom installation such as this. Downside is they do need to be kept hot - 70c is normal - so you are better ensuring there is additional insulation on them. 

At what price?

 

My replacement cylinder (after 32 years) cost £220, and I got 50 quid off the pikey when I scrapped it.  Unlike the 30 kg of 316 stainless steel I took to him, got nothing.

[Thedreamer]

1 hour ago, SteamyTea said:

Is that an easy thing to check out?

 

Seems you are pretty pleased with yours.

 

 

Yes, search the forum for ecocent or exhaust air source heat pump, the general feeling is negative to them.

 

Small heat pump, cylinder quality, Chinese manufacturing comes up a lot.

 

It almost put me off using one, but glad we stayed true to the plans.

 

Yes, if somebody is not going with underfloor heating and just need hot water they should be a consideration.