Radiator valves

[Tony Brooks]

If you are using compression fittings on plastic central heating pipe lease use metal pipe inserts to minimise the chance of leaks where the hot plastic creeps from under the olive. (better still pipe in copper).

[Tracy D'arth]

3 minutes ago, Tony Brooks said:

If you are using compression fittings on plastic central heating pipe lease use metal pipe inserts to minimise the chance of leaks where the hot plastic creeps from under the olive. (better still pipe in copper).

Good point.

 

I use 15mm copper tails in the valves down into push fit plastic tees. I used to do the whole job in copper but having to move with the times and the better frost protection means its usually plastic these days.

It used to be cheaper in copper with end feed fittings but its been a while so I am not so sure now.

[Keeping Up]

Our first boat's heating circuit was all copper. I was amazed when I saw how much the radiator at the far end would move as the copper expanded (the previous owner hadn't allowed for this and wondered why he kept getting leaks or broken radiator brackets)

[Tracy D'arth]

1 minute ago, Keeping Up said:

Our first boat's heating circuit was all copper. I was amazed when I saw how much the radiator at the far end would move as the copper expanded (the previous owner hadn't allowed for this and wondered why he kept getting leaks or broken radiator brackets)

The expansion is much worse with plastic! I hate the way it all goes wavy when hot no matter how many pipe clips you use. Plus there is little skill required, all those years of training and experience working copper and before that lead, are not needed now. I'm a dinosaur!

[Jackofalltrades]

Having seen how much hot plastic 22mm pipe expands over only a 10ft length I'd been wondering whether to use copper on our 60' narrowboat. The downside of copper though is much more heat loss and a pair of 22mm copper pipes + pipe insulation is bulky lump to hide down the length of the boat compared to 22mm plastic uninsulated pipe.

[jetzi]

9 minutes ago, Jackofalltrades said:

Having seen how much hot plastic 22mm pipe expands over only a 10ft length I'd been wondering whether to use copper on our 60' narrowboat. The downside of copper though is much more heat loss and a pair of 22mm copper pipes + pipe insulation is bulky lump to hide down the length of the boat compared to 22mm plastic uninsulated pipe.

Or, don't insulate it and it can contribute to your heating

 

I thought the main reason for not using solid copper on boats was work hardening through vibration.

 

I think as long as the pipe is in the wall and there is space for it to snake, I'll just let it be. There is already quite a lot of plastic pipe in place from the old system.

 

I notice that there is quite a bit of fine rust powder on the inside of this pipe though. So I'm wondering whether I should replace it or if I should just try to flush it out thoroughly.

[Chewbacka]

2 hours ago, Tracy D'arth said:

The expansion is much worse with plastic! I hate the way it all goes wavy when hot no matter how many pipe clips you use. Plus there is little skill required, all those years of training and experience working copper and before that lead, are not needed now. I'm a dinosaur!

Though it doesn’t look pretty, less clips is good as the expansion can be ‘lost’ in the wavy bits with less pulling and pushing as the plastic pipes contract and expand.

[Keeping Up]

I think the waviness is crucial. Plastic pipes can expand and make a snaky zig-zag whereas copper pipes stay straight and have to move the radiators.

[David Mack]

14 hours ago, jetzi said:

 

I think I need to find a more affordable coolant...

https://www.screwfix.com/p/flomasta-0623-concentrated-central-heating-inhibited-antifreeze-5ltr/4409r

[GUMPY]

10 hours ago, Jackofalltrades said:

Having seen how much hot plastic 22mm pipe expands over only a 10ft length I'd been wondering whether to use copper on our 60' narrowboat. The downside of copper though is much more heat loss and a pair of 22mm copper pipes + pipe insulation is bulky lump to hide down the length of the boat compared to 22mm plastic uninsulated pipe.

Loddon has an out and back run of 22mm copper feeding the radiators, up one side of the boat across the front down the other side and return along the same path. It is enclosed but with vents on the top of the enclosure so it contributes to the heating along the whole length of the boat. It also means that when the TRV on the front radiators shut down because the stove is on  there is enough, along with the bathroom rad, of a heat sink to prevent the Eber from cycling.

 

ETA the system was originally driven by a Kabola drip feed boiler so the heat leak had to work ?

Edited April 7, 2021 by Loddon

[Jackofalltrades]

2 hours ago, Loddon said:

Loddon has an out and back run of 22mm copper feeding the radiators, up one side of the boat across the front down the other side and return along the same path. It is enclosed but with vents on the top of the enclosure so it contributes to the heating along the whole length of the boat. It also means that when the TRV on the front radiators shut down because the stove is on  there is enough, along with the bathroom rad, of a heat sink to prevent the Eber from cycling.

 

 

When you say "an out and back run" I assume at the very end of the run the flow and return pipes are *not* connected together?

 

Part of me thinks having copper pipe (radiating more heat than plastic and expanding less) in a vented/grilled enclosure would be a good thing, but I can't help wondering if using plastic pipe with less radiated heat loss might be more efficient as the air is heated as designed rather than more randomly/everywhere there's a copper pipe. But the expansion of plastic pipe would be massive along the length of a 60' narrowboat. Using any pipe clips at all might be an issue at it would restrict expansion.

[GUMPY]

2 minutes ago, Jackofalltrades said:

When you say "an out and back run" I assume at the very end of the run the flow and return pipes are *not* connected together?

They are connected in a loop which extends 8-10 ft past the last radiator, you would think that this would take all the flow but there is enough pipe resistance in the last bit  to ensure the rads take most of the flow. The loop is about 70ft in length (140ft total) it has 3 drain taps one at each end and one in the middle to let air in when draining.

Whoever conceived it gave it a lot of thought.?

[David Mack]

11 minutes ago, Jackofalltrades said:

but I can't help wondering if using plastic pipe with less radiated heat loss might be more efficient as the air is heated as designed rather than more randomly/everywhere there's a copper pipe.

 

What 'design' goes into the radiator layout? You are trying to heat a space. The pipes will do that just as effectively as radiators. Indeed having heating from pipes at low level will be better in terms of avoiding the cold zone around your feet.

[GUMPY]

11 minutes ago, David Mack said:

 

What 'design' goes into the radiator layout? You are trying to heat a space. The pipes will do that just as effectively as radiators. Indeed having heating from pipes at low level will be better in terms of avoiding the cold zone around your feet.

 

What cold zone ? In our living area we have horizontal panel radiators 1200x200  rather than "normal" radiators.

Edited April 7, 2021 by Loddon

[Tracy D'arth]

13 hours ago, Jackofalltrades said:

Having seen how much hot plastic 22mm pipe expands over only a 10ft length I'd been wondering whether to use copper on our 60' narrowboat. The downside of copper though is much more heat loss and a pair of 22mm copper pipes + pipe insulation is bulky lump to hide down the length of the boat compared to 22mm plastic uninsulated pipe.

The expansion of a metre length of copper pipe heated from 10 deg C to 80deg C ( average heating temperature rise )  is only 1.2mm.

But the metre of Hep2O plastic pipe will expand 9mm for the same temperature rise.

 

So if you have say a 12 metre length of run that plastic pipe will become 108mm longer.  That is a lot of expansion!

Edited April 7, 2021 by Tracy D'arth

[Jackofalltrades]

33 minutes ago, Loddon said:

They are connected in a loop which extends 8-10 ft past the last radiator, you would think that this would take all the flow but there is enough pipe resistance in the last bit  to ensure the rads take most of the flow. The loop is about 70ft in length (140ft total) it has 3 drain taps one at each end and one in the middle to let air in when draining.

Whoever conceived it gave it a lot of thought.?

 

I had a feeling that's what you might have meant but it flies in the face of conventional two-pipe system design so thought, nah...

 

Presumably it works well or you'd have changed it. Food for thought. Maybe!

[Tracy D'arth]

2 minutes ago, Jackofalltrades said:

 

I had a feeling that's what you might have meant but it flies in the face of conventional two-pipe system design so thought, nah...

 

Presumably it works well or you'd have changed it. Food for thought. Maybe!

That would be a conventional boiler bypass loop then, required for domestic low water content boilers. In modern boilers it is an automatic built in bypass that operates at a set differential pressure.

Its not a bad idea with an Eber or Weber but I would fit a valve in the loop so that you could set the temperature differential when balancing the radiators.

For those interested, you normally balance radiators so that the difference between flow and return temperature is 20 deg C then balance the flow with the bypass so that the temperature difference across the boiler is 20 dg C too. Takes a bit of to and fro altering all the valves but ensures the best operating conditions.

[Jackofalltrades]

22 minutes ago, Tracy D'arth said:

The expansion of a metre length of copper pipe heated from 10 deg C to 80deg C ( average heating temperature rise )  is only 1.2mm.

But the metre of Hep2O plastic pipe will expand 9mm for the same temperature rise.

 

So if you have say a 12 metre length of run that plastic pipe will become 108mm longer.  That is a lot of expansion!

 

I've never seen the difference in expansion rates quantified before but those figures ring true based on my experience. It does make it hard to envisage using plastic pipes for heating on a narrowboat with relatively long pipe runs. Copper pipe might work harden over time but those plastic pipe fittings that grip with sharp blades and seal with O rings must be subject to a fair amount of wear over time due to expansion & contraction.

 

[GUMPY]

1 minute ago, Jackofalltrades said:

 

I had a feeling that's what you might have meant but it flies in the face of conventional two-pipe system design so thought, nah...

 

Presumably it works well or you'd have changed it. Food for thought. Maybe!

When I first got the boat and fitted the Eber I did mentally query it but CBA at the time to do anything about it, it has functioned well for 8 years so not changing it now. It does mean that the pipe will act as a heat leak during the summer if I need to get hot water from the Eber.

[Tracy D'arth]

8 minutes ago, Jackofalltrades said:

 

I've never seen the difference in expansion rates quantified before but those figures ring true based on my experience. It does make it hard to envisage using plastic pipes for heating on a narrowboat with relatively long pipe runs. Copper pipe might work harden over time but those plastic pipe fittings that grip with sharp blades and seal with O rings must be subject to a fair amount of wear over time due to expansion & contraction.

 

I have never had a brittle fracture problem with properly installed copper pipework on boats. My own boat is over 30 years old, all copper, and touching wood, never had a leak. There was a problem with copper when restrained  tightly like in flooring screeds but the expansion is so small that it usually finds some where to go without flexing the pipework too much.

As for vibration causing work hardening, that is down to proper fitting so that the pipes do not vibrate.  Plenty of clips in the right places solves that.

I would not use thin wall hard drawn copper pipe anywhere, gas should be in soft drawn pipe, table X drawn pipe for everything else.

Edited April 7, 2021 by Tracy D'arth

[Jackofalltrades]

1 minute ago, Loddon said:

When I first got the boat and fitted the Eber I did mentally query it but CBA at the time to do anything about it, it has functioned well for 8 years so not changing it now. It does mean that the pipe will act as a heat leak during the summer if I need to get hot water from the Eber.

 

My heating design & installation has mainly been domestic (house renovations) + fitting a Thermo Top system to a lumpy water boat. All of the above have been conventional two-pipe systems with no connection between the flow& return at the end of the pipe runs. I can see the logic though with the need to avoid cycling on the Eber/Webasto systems. Do you have a balancing valve fitted at the end, as per @Tracy D'arth's comment above?

 

[Jackofalltrades]

1 minute ago, Tracy D'arth said:

I would not use thin wall hard drawn copper pipe anywhere, gas should be in soft drawn pipe, table X drawn pipe for everything else.

 

Whoosh. that went straight over my head I'm afraid. Not sure where the mention of gas came from. I'm purely talking about pipe for wet heating systems to connect boiler to radiators & calorifier. If I do decide to use copper pipe for the heating system my usual port of call would be a plumber's merchant - not sure how that everyday regular plumbing pipe fits with your statement?

[GUMPY]

7 minutes ago, Jackofalltrades said:

. Do you have a balancing valve fitted at the end

Not that I have ever found?

It started life being driven by a diesel drip feed Kabola E5 boiler

http://www.zag.ee/en/kabola/heating_systems/?cat_id=9

which can't be shut down quickly in the event of no water flow.

Good boilers, better than the Eber but it meant the bedroom was too warm with it in the cupboard.

Edited April 7, 2021 by Loddon

[jetzi]

1 hour ago, Loddon said:

They are connected in a loop which extends 8-10 ft past the last radiator, you would think that this would take all the flow but there is enough pipe resistance in the last bit  to ensure the rads take most of the flow. The loop is about 70ft in length (140ft total) it has 3 drain taps one at each end and one in the middle to let air in when draining.

Whoever conceived it gave it a lot of thought.?

The previous design in my boat (which never worked well) had a out and back run, with only a calorifier (no valves), a towel rail (with valves) and one rad (with valves). Directly after the rad the flow and return were connected in a loop. The towel rail never got hot when I tried the eber, the rad got warm but not hot enough. Hence I relied on my solid fuel stove and didn't use the Eber. The rad eventually sprung a leak and so I ripped it and the towel rail out. I assumed there was a problem with the Eber so I had it professionally serviced. I now want to reinstall it - I am thinking that I'll not include the direct connection of the out and back pipes. I'll put valves on all the rads but I will not ever turn the towel rail off. I'll then use the lockshield outlet valve to try to balance the rads.

 

This should work, right?

[Jackofalltrades]

11 minutes ago, Loddon said:

Not that I have ever found?

It started life being driven by a diesel drip feed Kabola E5 boiler

http://www.zag.ee/en/kabola/heating_systems/?cat_id=9

which can't be shut down quickly in the event of no water flow.

Good boilers, better than the Eber but it meant the bedroom was too warm with it in the cupboard.

 

See, if something goes wrong with your heating you can always blame the doofus that originally fitted it. To my other half I will be that doofus.