Gas central heating boiler kettling, testing weak circulation pump?

[Wedg1e]

Gaz, I'll blame you for the cr@p single-pipe system in my mother's house then
It was the latest thing when we moved in, August 1970... then the boiler had to be converted to natural gas and would keep blowing out.
In the late 80s my uncle managed to get us a new system boiler with his staff discount: he worked for Potterton.
It's still in and it still works but unless it was firing 24 hours a day you'd never feel the effect of it. Having it on timer for 2 hours, twice a day does nowt apart from spin the gas meter. All the piping is 15mm (it might even be half-inch) and none of it is lagged, above or below the floors. The pump only circulates through the rads, the DHW is thermosyphon only - not so much as a diverter valve in it!
I know the proper fix is to strip it all out and start again but, money aside, the old dear wouldn't stand for it. Pushing 80, too much disruption... I had to replace the galvanized header tank last year and she grumbled about the mess in the airing cupboard!

 

[brightspark]

last house i put in gravity hot water pumped heating with back boiler. this house i put a conventional boiler in y plan 10mm bore pipes and thermostatic rad valves. much more efficient

 

[gaz1]

Gaz, I'll blame you for the cr@p single-pipe system in my mother's house then
It was the latest thing when we moved in, August 1970... then the boiler had to be converted to natural gas and would keep blowing out.
In the late 80s my uncle managed to get us a new system boiler with his staff discount: he worked for Potterton.
It's still in and it still works but unless it was firing 24 hours a day you'd never feel the effect of it. Having it on timer for 2 hours, twice a day does nowt apart from spin the gas meter. All the piping is 15mm (it might even be half-inch) and none of it is lagged, above or below the floors. The pump only circulates through the rads, the DHW is thermosyphon only - not so much as a diverter valve in it!
I know the proper fix is to strip it all out and start again but, money aside, the old dear wouldn't stand for it. Pushing 80, too much disruption... I had to replace the galvanized header tank last year and she grumbled about the mess in the airing cupboard!

im not that old

im just aware of old systems due to the area i live within that still use them

ive seen the old steam central heating pipes still in use to this day
the one pipe system you mention of even kayos has seen that old system it still exists in some houses and buildings

its like the old soil stack airing/anti vac system it still exists in my area

old houses and old buildings still have the old methods still in use to this day shame the new methods dont last as long as the old systems that includes the old cast iron floor standing boilers that need very little to repair on them just a heat stat a brurner clean and away they go again
compared to a new boiler that fails in 6-10 years lucky if one lasts 15 years but the old ones still work 40 years later

 

[Wedg1e]

I must be missing something but the 8 and 10mm microbores don't seem to me like they could be more efficient?
My combi has 6m long 22mm flow and return along the spine of the loft with 15mm drops to each rad, fully felt-lagged even inside the walls... now THAT's efficient
20 seconds after ignition the rads start to feel warm.

My exes place had miles and bloody miles of 8mm, fed from an oil boiler at the furthest point of the house.
It took weeks for the bedroom rads to warm up
Actually, now I think about it: she had the back boiler taken out (by me ) - the previous owners kept a massive coal fire lit 24 hours so the rads would have been circulating off the back boiler. Her argument was that she wouldn't be using a coal fire when out at work.
So I took the fire and back box out and she had a new fire put in. A coal fire. Just for show

 

[brightspark]

I must be missing something but the 8 and 10mm microbores don't seem to me like they could be more efficient?
My combi has 6m long 22mm flow and return along the spine of the loft with 15mm drops to each rad, fully felt-lagged even inside the walls... now THAT's efficient
20 seconds after ignition the rads start to feel warm.
My exes place had miles and bloody miles of 8mm, fed from an oil boiler at the furthest point of the house.
It took weeks for the bedroom rads to warm up

a combi would be no good in my house its 2 big.the heating is run from the boiler in 22mm pipe to 2 no 6 way manifolds one on each side of the house and 10mm runs to rads. it heats up quick and hardly any heat loss in the pipes if it was 15mm more aria to disipate heat

 

[Wedg1e]

old houses and old buildings still have the old methods still in use to this day shame the new methods dont last as long as the old systems that includes the old cast iron floor standing boilers that need very little to repair on them just a heat stat a brurner clean and away they go again
compared to a new boiler that fails in 6-10 years lucky if one lasts 15 years but the old ones still work 40 years later

One of the guys at work blagged a load of cast-iron rads from an MOD site in Scotland that was being refitted.
He had them all blasted, pressure tested, acid cleaned and whatever else and put them in his 17/18/19th century cottage (actually 3 cottages knocked into 1) - he got that many he needed a twin-axle plant trailer to bring them down. We chucked the last three, leaky ones, onto a scrap pile last week.
Would have cost a mint to buy new, even if you still could.

 

[Wedg1e]

a combi would be no good in my house its 2 big.the heating is run from the boiler in 22mm pipe to 2 no 6 way manifolds one on each side of the house and 10mm runs to rads. it heats up quick and hardly any heat loss in the pipes if it was 15mm more aria to disipate heat

Fair point, I was working on moving the thermal mass around quicker (less resistance in the larger pipes).
My combi is over-specced for the house (apparently a big no-no these days) - I bought it from a lotto win in 2005 and although I only needed the 82,000 btu one, for £100 more I got the 102,000 btu. Well, it was found money

It has its ups and downs, I've swapped a few bits on spec over the years to see if issues would clear up. I think it needs a larger expansion vessel even though the specs say with the amount of rads and pipe I have it should be within the ability of the onboard one to cope - but it keeps blowing the PRV and dropping pressure. Not the end of the world; I just shin up the loft ladder and turn a tap.
A year or two back I ran in some new pipes to fit a plinth heater in the kitchen as I was planning to remodel; there's no heating in there. With the extra water volume it may well need a bigger expansion vessel so may as well fit one and have done with it.
Mind you - have you seen the price of water-fed plinth heaters?!

 

[Morrisman]

ive seen the old steam central heating pipes still in use to this day
the one pipe system you mention of even kayos has seen that old system it still exists in some houses and buildings

My ex wife's aunt has one of those in her house in Brooklyn, they couldn't work out why some rads didn't work properly. Ten minutes on google, a visit to Walmart DIY and I fitted a couple of new air vent valves and all was good. It's a strange system, but used all over New York.
Where you see steam pouring out of the ground in old movies, it's real, they pump steam heating all over the city.

 

[dobbslc]

Gaz, I'll blame you for the cr@p single-pipe system in my mother's house then
It was the latest thing when we moved in, August 1970... then the boiler had to be converted to natural gas and would keep blowing out.
In the late 80s my uncle managed to get us a new system boiler with his staff discount: he worked for Potterton.
It's still in and it still works but unless it was firing 24 hours a day you'd never feel the effect of it. Having it on timer for 2 hours, twice a day does nowt apart from spin the gas meter. All the piping is 15mm (it might even be half-inch) and none of it is lagged, above or below the floors. The pump only circulates through the rads, the DHW is thermosyphon only - not so much as a diverter valve in it!
I know the proper fix is to strip it all out and start again but, money aside, the old dear wouldn't stand for it. Pushing 80, too much disruption... I had to replace the galvanized header tank last year and she grumbled about the mess in the airing cupboard!

When I moved to my new house it was a quick and rude education in single pipe and gravity systems, a 40 year old oil boiler and blocked / leaking pipes and rads!

a combi would be no good in my house its 2 big.the heating is run from the boiler in 22mm pipe to 2 no 6 way manifolds one on each side of the house and 10mm runs to rads. it heats up quick and hardly any heat loss in the pipes if it was 15mm more aria to disipate heat

That sounds very similar to mine except I used 15mm Kuteluex pipe on a coil so I don't have any under the floor.