Upgrade of old plumbing system, Solid Fuel Rayburn, Well Water, Oil boiler

[Nickfromwales]

7 minutes ago, Iceverge said:

Maybe a primatic cylinder? 

That’s what I’ve been thinking for some time…..

Header tank is way too small, so when low the splashing water from the fill valve stirs up the sediment.

 

Extra Radox is recommended lol.

[Iceverge]

Lol, 

 

It's all going to be turfed out into the garden shortly soon anyway! Further measurements have concluded that a combi thermal store would be too tall to allow the gravity return to be above the bottom of a direct T/S .I've revised my plan to put a new copper/galvanized header tank in the attic and run the rads directly from the store whilst dispensing with the existing F+E for the CH. 

 

 

 

Does the above system look logical from a plumbing point of view?  

[HughF]

Ah, a posh version of my system in Dorset. Except I’ve got a stainless back boiler in a mk1 Rayburn. And no central heating 😉
 

The only thing I would add: please fit a laddomat to that 355. The back boilers are weak, and complicated/expensive to replace. The 355 doesn’t like being taken apart to have it changed. Not the finest Rayburn, but certainly the most capable.

Edited September 15, 2022 by HughF

[SteamyTea]

On 18/08/2022 at 15:26, Iceverge said:

I think there was a terrible case somewhere in SW England a few years back I think when a tank came through the ceiling. 

Was near me.

http://news.bbc.co.uk/1/hi/england/cornwall/3035606.stm

 

I think there was another one involving a child.

 

Depending on the type of resin used, GRP should be acceptable, but may not be legal and it is still best to to put the tank above the bed.

Edited September 16, 2022 by SteamyTea

[HughF]

If you batch fire the 355 in the shoulder months then I would suggest you fit a flap type non return valve, with the spring removed, in the hot side of the gravity loop. This will prevent thermosyphoning back through the Rayburn when the fire is out and the TS is hot.

 

If you have a long distance between the 355 and the TS then you might want to consider siting the laddomat at the TS. That way when the stat opens in the laddomat it won’t push a huge slug of cold water into the top of the TS.

 

I’ve helped my Dutch friends with a similar install to this, 355 and a polish 50kW peat burner (think beeston sectional domestic) firing direct into a pair of close coupled 800ltr buffers. 4 mixed zones off the buffer, solar coil in the base of one and DHW coil in the top of the other.

 

Endless free hardwood pallets fuel their heating system.

Edited September 16, 2022 by HughF

[SteamyTea]

1 hour ago, HughF said:

Endless free hardwood pallets fuel their heating system.

Probably illegally though.

[Iceverge]

I've moved this on just a little since. 

 

Collected a 250 Maxipod thermal store from CopperIndustries/LB cylinders yesterday. It wasn't cheap at €2k but hopefully it'll do the trick. 

 

Also bought a galvanized F+E tank for the attic. Hopefully I'll get around to install sometime in the next few months. 

 

The gravity pipework from the Rayburn and the F+E tank will be done in 1" copper. 

 

Reading the various regs and MI's I can't see anything prohibiting me fitting the heating circuit in 22mm Hep2o and the oil boiler feed in same. (1 Meter need the boiler needs copper i know)

 

Anyone know much better? 

 

Also I know Hep2o can be push fit to metric copper. Is this acceptable or is it preferrable to use a compression fitting and then a brass to Hep2o? 

 

 

VS

 

  PLUS 

4 hours ago, SteamyTea said:

best to to put the tank above the bed

Noted. 

 

3 hours ago, HughF said:

This will prevent thermosyphoning back through the Rayburn when the fire is out and the TS is hot.

 

 

Hopefully the elevation of the TS will prevent this? 

 

3 hours ago, HughF said:

long distance between the 355 and the TS

 About 3-4m, I'm going to try without a laddomat. The current cylinder functions fine at the moment. 

[SteamyTea]

3 minutes ago, Iceverge said:

4 hours ago, SteamyTea said:

NOT best to to put the tank above the bed

Noted. 

If you can fit a tank above a bath, if it does leak, at least there is something watertight below it to catch the water.

[Iceverge]

Right @ plumbing gurus. 

 

I need to run new hots and colds to a bathroom. 

 

It will supply. 

 

1 X WC. 

1 X Hot Basin

1. X Cold Basin

1 X Mixer thermostatic shower

1 X Electric shower.

 

 

Unfortunately the routing of these requires pulling down lots of plasterboard and drilling joists. I would prefer a radial system of 15mm for the showers and 10mm for everything else but I think I'm stuck with a trunk and branch layout. 

 

What is the minimum amount of pipes recommended for this. 

 

I was thinking 1x 15mm hot. 1 X 15mm cold and 1x 10mm hot for the basin. 

 

 

 

 

 

[Nickfromwales]

The 10mm for the bacon will only be effective if it’s the first thing T’d off the outlet of the hot water device. You want zero dead leg if going to the effort of installing a dedicated 10mm basin feed. 
Will be worth the effort. 

[Iceverge]

Yes this is what I was planning. A dedicated 10mm hot feed taken from as close to the TMV on the cylinder as practical - direct to the basins. 

 

Will a 1X15mm cold feed should be ok for a thermostatic mixer shared with an electric 8kw Shower? They're unlikely to be used together. 

 

At the moment when you flush the loo or run the basin cold tap the shower goes weak and scorching as the water flow in the electric shower drops to about 3l/min. I think this is because they are all sharing a 1/2" MDPE supply. 

 

A dedicated 15mm supply to electric shower should stop this I hope. 

 

The basin and WC will share another 15mm that splits into 2x10mm for the end of the run. 10mm as it is easier to conceal and will limit the draw of water. 

 

The thermostatic shower will get a 15mm hot too. 

 

Any other bear to traps I'm going to step into? 

[Iceverge]

On 10/11/2022 at 16:44, Iceverge said:

Will a 1X15mm cold feed should be ok for a thermostatic mixer shared with an electric 8kw Shower? They're unlikely to be used together. 

 

That mystery 1/2" pipe neither leaves the pump house nor gets teed off the mains pipe anywhere in the house. It simply emerges from the concrete producing water. I've decided to leave it but cap the basin and W/C and feed them from the mains as well as the new shower. 

 

I was wading through guano earlier in the attic shuffling the new F+E into place thinking about how to plumb it in. 

 

 

A typical cylinder is fed something like this AFAIK. 

 

 

 

 

With a thermal store can i plumb as below. as there is no direct hot water draw off. Allowing the F+E pipe to keep the cylinder topped up too? 

 

 

 

 

 

 

 

 

 

 

 

 

 

[dpmiller]

you'll be pushing heated water out of the store when it expands tho?

[Iceverge]

I don't see how it'd be different from the other system. 

 

Maybe I'm missing something? 

[SteamyTea]

12 hours ago, Iceverge said:

 

Maybe I'm missing something? 

When liquid water changes to steam it expands, by around 1700 times.

It is the steam you need to worry about, not the thermal expansion of liquid water.

[Blurred22]

Hi. Just  wondering how you got on with this?

[Miek]

The cylinder should have a horizontal pipe on the top outlet to prevent 'one pipe' circulation where hot water passes up the pipe center and down the cooler pipe walls in a convection current. if you have a vertical pipe you waste a lot of heat. 500mm is plenty of horizontal before you go vertically to the F&E tank.

[Iceverge]

10 hours ago, Blurred22 said:

Hi. Just  wondering how you got on with this?

Still at it. 

It's slow progress, waiting for taps ATM. 

 

 

2 hours ago, Miek said:

The cylinder should have a horizontal pipe on the top outlet to prevent 'one pipe' circulation where hot water passes up the pipe center and down the cooler pipe walls in a convection current. if you have a vertical pipe you waste a lot of heat. 500mm is plenty of horizontal before you go vertically to the F&E tank.

 

 

Gottya.  I was wondering about this. Its happening by necessity anyway due to the location of the cylinder. The install diagram is now the same as the first one too except the draw off diagram. 

 

[Iceverge]

Managed to get this done just before Christmas. 

 

Used a 250l Maxipod from copper industries . Not cheap at about €2k but it seems to be well made and has a 25 year guarantee.

 

I installed a new galvanised tank in the attic as a header tank, this leaked at a corner but I plugged it with a small bit of silicone. 

 

I was keen to avoid any joints in the pipes, especially in inaccessible areas so it looks a bit messy where I've curved them into the ceiling space etc. As I was limited on time and skills I didn't want to pull down any ceilings or dig up floors. All pipes were routed behind cabinets etc except across one ceiling where I put them in conduit. 

 

I used Hep20 manifolds and a radial layout for the hot water with 10mm to the kitchen tap and all basins. It results in a very quick time to hot. About 6l/min at the kitchen tap which is fine. 15mm everywhere else and the flow rate is about 10l/min at the bath taps. Picked up a Triton mixer from Screwfix which works very well. In fact the DHW performance is as good as the UVC in our own house. I don't know how long the DHW lasts but it seemed to satisfy 5 adults over Christmas so it can't be too bad. The hot tap is fresh water also which is nice and there's no servicing as per UVC's etc. I think I may consider one when the SS cylinder in our own house gives in.  

 

The store is mainly heated by a Rayburn 355SFW burning a mix of soft and hardwoods on a thermosyphon/gravity circuit. It burns for about 12hrs a day so no shortage of input. I just used one pump for the CH which turns on when the bottom of the tank gets hot to circulate the water through the radiators. 

Thermosyphon is proportional to the temp difference between flow and return and height of the tank. I really had nowhere else to put the tank so it's base is only about 150mm above the top of the cooker and 2m horizontally away. This limits the amount of heat transfer we can get from the cooker so the rads typically never get much above lukewarm. This is fine as the long duration of burn has made the house very comfortable for the first time ever! 

The oil boiler is just on a timer and heats the tank directly. When the bottom of the tank is hot the CH pump kicks in on a thermostat. As the oil boiler is probably about 3 times more powerful than the cooker it has no problem with the rads but there is a lag between it coming on and heating the house, it has the benefit of heating the DHW proportion first however. 

 

Any other questions fire away. 

 

 

 

 

[HughF]

Nice job….. hard to beat a Rayburn if you’ve got the wood/time to fuel it. My mk1 has been ‘in’ 24/7 since 2nd November. Coal man comes again on Tuesday 🤣

 

My Dutch friends have a 355 running into a 1600ltr buffer tank with a dhw coil, batch fired. Does all their cooking, heating and hot water, except when it’s very very cold out and they then batch fire a 40kW log burner into the buffer tank also.