Commissioning UFH with no mains gas

[Grosey]

As the title states, I'm in a bit of a pickle. There is major works required in order to connect my mains gas. I also need to commission my UFH before I can bring in my engineered oak flooring / oak door etc (if I am wrong in this part please do let me know!)

 

Currently the plan is to knock together some sort of temporary calor gas boiler arrangement, plumber mate has managed to acquire an old gloworm boiler he thinks he can convert to LPG. We will probably set this up temporarily outside or in the garage. 

 

 

Before I head off down this road I thought I'd check here that i hadn't missed any other obvious solutions? And that's i am correct in needing to have fired up the heating and warmed the slab through before I bring in any of my solid wood products?

 

Oak flooring will be stuck down if that makes any difference?

 

Thanks all

[Nickfromwales]

3kw Willis heater ? 5 minute retro fit into your intended system and near zero doing  / undoing and no pointless boiler installing. . 

[JanetE]

1 minute ago, Nickfromwales said:

3kw Willis heater ? 5 minute retro fit into your intended system and near zero doing  / undoing and no pointless boiler installing. . 

This is exactly what we have, with no intention of having gas. It will run all of our UFH.

[Grosey]

Is that an immersion heater? I did ask my plumber if the heating could be run off an immersion heater, not sure exactly what he said but didn't seem to be a go-er. 

 

Ive got a Vailliant 38kw system boiler going in if that is useful info?

 

Where abouts within the system would the Willis heater go?

Edited August 6, 2017 by Grosey

[PeterW]

Willis is an immersion in a small enclosure - link it between the hot flow and the return from the loops and then turn it down low. Wire into a 13a plug if you need to as it's only 3kw

 

External Immersion Heater (also known as a Willis) https://www.amazon.co.uk/dp/B00XLBAAEG/ref=cm_sw_r_cp_api_vI5Hzb919R4J9

 

Its an hours job for the plumber. 

 

 

[Grosey]

I knew asking on here first was a good idea ?

 

 

For Sale: Old Gloworm Boiler - not yet converted to LPG ?

[PeterW]

If you do it, turn the blending valve right up so you can't get water stagnating in the Willis.   Let the Willis thermostat set the flow temperature. 

[Jimbouk]

Intriguing, is this really a viable heat source for UFH medium term? I have circa 85m2 of floor area, was going to have a megaflow for the hot water store, now wondering if I can ditch / postpone the mains gas connection and boiler?

 

it is for a holiday home, so not too much constant use, but will need to get up to temperature when using in the Winter.

[Guest Alphonsox]

We are using a 3Kw immersion to heat our 100m2 UFH floor area. We are running it from E7 electricity only (So it doesn't run at all during the day). So far it seems very successful but we haven't moved in full time and don't have the MVHR active yet. Whether it will work for you will depend on the level of insulation and airtightness you have in place.

[PeterW]

33 minutes ago, Jimbouk said:

Intriguing, is this really a viable heat source for UFH medium term? I have circa 85m2 of floor area, was going to have a megaflow for the hot water store, now wondering if I can ditch / postpone the mains gas connection and boiler?

 

it is for a holiday home, so not too much constant use, but will need to get up to temperature when using in the Winter.

 

As @Alphonsox says it's all to do with heat load. If you have a low enough load then using a 3kw Willis on E7 will work fine. @TerryE is planning something similar too, using Sunamps for DHW. 

 

The downside with this for a holiday home (especially if you let it out) is that you don't know what DHW usage you will get from week to week and standard electric tanks can take a while to recover unless you put pairs of immersions into the tank.  

[Nickfromwales]

1 minute ago, PeterW said:

 

As @Alphonsox says it's all to do with heat load. If you have a low enough load then using a 3kw Willis on E7 will work fine. @TerryE is planning something similar too, using Sunamps for DHW. 

 

The downside with this for a holiday home (especially if you let it out) is that you don't know what DHW usage you will get from week to week and standard electric tanks can take a while to recover unless you put pairs of immersions into the tank.  

@Crofter is doing just that in his modest holiday rental . Just size the cylinder bigger for a bigger let ?

If in any doubt, just fit 2 Willis heaters in series, not parallel, and then you've got 6kw. . Cheap as chips and you'll sell them on when your done. 

[Nickfromwales]

8 hours ago, Grosey said:

 

Ive got a Vailliant 38kw system boiler going in if that is useful info

Ok, another option for you. 

The vailant gas valves will switch to LPG in the time it's taken to write this. It's just a screw adjuster on the side of the gas valve, and the circa £7-8 for the 'LPG conversion kit' just buys you a yellow sticker saying "Converted to LPG" !!!!

If your gas meter is going outside then just hook up a 47kg bottle/s, connect it accordingly to the 22/28mm gas feed to the house, and run the 638 on LPG for the meantime ?

Oh, and tell your plumber the Willis heater will do the job for space heating, as long as your reasonably insulated and have windows etc, it'll just take a full day to get up to temp. If it's struggling do as I say above and fit two. 

 

Edited to add : check with LPG gas regs, iirc you may need an internal emergency gas shut off valve ( EGC ) and an internal test nipple. Your plumber will know this if he's LPG qualified. 

[Jimbouk]

29 minutes ago, PeterW said:

 

As @Alphonsox says it's all to do with heat load. If you have a low enough load then using a 3kw Willis on E7 will work fine. @TerryE is planning something similar too, using Sunamps for DHW. 

 

The downside with this for a holiday home (especially if you let it out) is that you don't know what DHW usage you will get from week to week and standard electric tanks can take a while to recover unless you put pairs of immersions into the tank.  

 

What a great start to a Monday morning! Hoping we will not have to rent it out, as you suggest would put a pair in the megaflow.

 

The UFH Heatmiser Neo system is going to be remote controlled over the web, so just need to check that they do an immersion load switch in their range. Then I can use the setting to configure only having the UFH working at night when the house is empty, just to keep the chill off, but enable daytime use if required when being lived in. Equally should be able to remotely enable the immersions so that we have hot water on arrival.

 

Whilst not in Passivhaus territory, hoping to be far better than building regs in terms of airtightness and insulation, combined with some deliberate Winter solar gain, MVHR too.

 

Looks like I might not be needing the gas supply pipe we laid after all! Not had it connected yet and always like a bit of future proofing..

 

@Grosey sorry for hijacking your thread!

Edited August 7, 2017 by Jimbouk

[Guest Alphonsox]

45 minutes ago, Nickfromwales said:

@Crofter

If in any doubt, just fit 2 Willis heaters in series, not parallel, and then you've got 6kw. . Cheap as chips and you'll sell them on when your done. 

@Nickfromwales, Care to elaborate on this - why is a series arrangement preferable to a parallel set up when it comes to Willis ?

[PeterW]

31 minutes ago, Jimbouk said:

The UFH Heatmiser Neo system is going to be remote controlled over the web, so just need to check that they do an immersion load switch in their range

 

You don't need to do that .....

 

Neo can output either volt free or 230v signal to the boiler (it's a jumper setting I think) and then link that to a decent SSR or contractor that will then control the immersion. 

[Jeremy Harris]

8 hours ago, PeterW said:

Wire into a 13a plug if you need to as it's only 3kw

 

 

Don't do this, as a BS1363 plug and outlet is only normally rated for a maximum continuous load of  around 10A.  13A is the intermittent maximum load rating, and a 3kW heating element that is rated at the nominal standard UK mains voltage of 230 VAC will draw just over 13 A at 230 VAC, and over 14.3 A at the maximum UK supply voltage of 253 VAC.

 

 

[PeterW]

18 minutes ago, JSHarris said:

 

Don't do this, as a BS1363 plug and outlet is only normally rated for a maximum continuous load of  around 10A.  13A is the intermittent maximum load rating, and a 3kW heating element that is rated at the nominal standard UK mains voltage of 230 VAC will draw just over 13 A at 230 VAC, and over 14.3 A at the maximum UK supply voltage of 253 VAC.

 

 

 

Wrists slapped - @JSHarris is correct ..! 

[Jeremy Harris]

7 minutes ago, PeterW said:

 

Wrists slapped - @JSHarris is correct ..! 

 

@PeterW, to be honest, I had no idea about this potential problem until I bought the Plug-in Prius.  I was puzzled by the fact that the charge point lead that came with the car only charged at a maximum of 2.2kW. A bit of digging around revealed that the charge current was deliberately limited when using the 13A lead, to prevent overheating the BS1363 plug, and a bit more digging discovered that the 13A rating for the plug is the maximum intermittent load rating, not the maximum continuous load rating.

[Nickfromwales]

52 minutes ago, Alphonsox said:

@Nickfromwales, Care to elaborate on this - why is a series arrangement preferable to a parallel set up when it comes to Willis ?

Just to get a more uniform delivery from the heaters. Two in parallel would require the pipework to each heater to be near identical to guarantee even flow through both heaters, just my OCD from that point probably.

More on point though, with the series arrangement the secondary heater can then also be set to a much lower temp to 'kick out' when the system is up nearer to operating temp = or < the 3kw of one heater. Should add longevity to the system as the secondary heater should spend a lot of its time off as it'll only really be needed for starting the system from cold / adverse conditions. 

IMO it's better to have one running near constant than two switching in and out like yo-yo's. 

[Grosey]

1 hour ago, Nickfromwales said:

Ok, another option for you. 

The vailant gas valves will switch to LPG in the time it's taken to write this. It's just a screw adjuster on the side of the gas valve, and the circa £7-8 for the 'LPG conversion kit' just buys you a yellow sticker saying "Converted to LPG" !!!!

If your gas meter is going outside then just hook up a 47kg bottle/s, connect it accordingly to the 22/28mm gas feed to the house, and run the 638 on LPG for the meantime ?

Oh, and tell your plumber the Willis heater will do the job for space heating, as long as your reasonably insulated and have windows etc, it'll just take a full day to get up to temp. If it's struggling do as I say above and fit two. 

 

Edited to add : check with LPG gas regs, iirc you may need an internal emergency gas shut off valve ( EGC ) and an internal test nipple. Your plumber will know this if he's LPG qualified. 

 

 

That was was another option which was discussed, there was just concern about whether it could be switched back to natural gas again once we are ready? Don't want to boll***s up a £1500 boiler obviously. 

[Nickfromwales]

You can change it daily if you want. All you need is a suitable sized manometer for LPG, whack it up to 37mb working pressure and Roberts ya mothers brother. All you'll need to do is purge each time to get the correct gas to the valve. 

"Simples"

[Temp]

There are lots of 3kW fan heaters around that come with a standard 13A plug so it can't be too bad a problem?

[Jeremy Harris]

5 hours ago, Temp said:

There are lots of 3kW fan heaters around that come with a standard 13A plug so it can't be too bad a problem?

 

They are a problem, in that plugs do overheat if they are run for long periods on maximum power.  A 3kW 230VAC rated heater will draw 13.6A at 240VAC, for example, above both the plug and the fuse continuous rating.  240VAC is probably closer to the average supply voltage in the UK than the nominal 230VAC that it's supposed to be, because of the way we've bodged the tolerances in order to comply with a harmonised supply voltage.  We didn't ever change anything when the UK system switched from 240VAC to 230VAC, we just made the tolerance asymmetric, so it's 230VAC +10%, -6%, whereas much of Europe is 230VAC +6%, -10%.  That means our 230VAC nominal supply can be as high as 253VAC, or as low as 216VAC, but tends to still be around 240VAC much of the time, as it used to before harmonisation................

 

These heaters often have a thermostatic control, and rely on that reducing the duty cycle in operation so that the plug doesn't overheat.  Frankly I don't think that's sensible, but it is allowable under the way they are tested.

 

If anyone doubts that a 3kW load will overheat a good quality BS1363 plug, fitted with a decent BS1362 fuse, then poke a thermal camera at one that's been loaded for a time and see what it looks like.

 

As a final point, there are a lot of fake BS1363 plugs, and BS1362 fuses around on the market.  There are various exposés of these around on the web, illustrating some of the shortcomings of the many fakes.  The favourite trick with fake fuses is not to fill them with sand, so they become a fire hazard - something that's hard to tell from a quick look at a fake.

Edited August 7, 2017 by JSHarris

[Grosey]

On 8/7/2017 at 09:45, Nickfromwales said:

You can change it daily if you want. All you need is a suitable sized manometer for LPG, whack it up to 37mb working pressure and Roberts ya mothers brother. All you'll need to do is purge each time to get the correct gas to the valve. 

"Simples"

 

We have decided to go for this method and I need to get a bottle of gas. Any advice, Calor / Flo Gas / Propane / Butane...? I clearly don't know a great deal about LPG!

 

Also what size bottle, I'll need to run the heating for 5-10 days I guess so I'd imagine one of the big approx 5ft bottles?

[Nickfromwales]

It'll be the orange propane iirc.

 

14 minutes ago, Grosey said:

I clearly don't know a great deal about LPG!

 

TBH your gas fitter needs to advise you properly. I take it your not doing this yourself?

Gas + hero = bigbaddaboom .