Gravity conversion?

Paul S_3

the pics below show a radiator, return elbow on a radiator and a main with standard 2.5 tees pointed on a 45 degree angle downwards these from @Dan Holohan s books i know right off the bat was for the upstairs radiators.....i gave 3 quotes (1) stay with gravity using a weil mclain (knockdown) CI boiler ......(2) convert to pumped circulation with a atmospheric CI boiler and 4 way Taco ISERIES on constant circulation......(3) which is the most ideal was convert to pumped circulation using modcon Lochnivar khn .....system pump on constant circulation......which setup would you guys go for? any advice? Do you guys think these are standard return elbows? orifice plates on top floors? i did not open radiator valves or return elbows yet.....when converting to pumped circulation can i run into any problems.....system not open to atmosphere.....theres a steel compression tank at boiler.....thanks for any input....ive seen @gerry gill install a straight gravity boiler using a Honeywell #1 heat generator.....maybe you have some tips too.....never converted or replaced a gravity system . boiler...heat loss for home is no more than 100k at most from experience....every radiator is similar to the one in the pic all from 25 sections the smallest rad to 40 sections the largest .thanks Paul S

Paul48

That's an odd set up. I could see a return looking like that, but in your photo they tapped off the supply and return, more or less, from the bottom of the pipe.

Paul S_3

I think they did that to slow down the circulation to the top floors ...so the lower floors heat pretty much the same time for system balancing.....that's why I don't think there's orifice plates in the top radiators....never done this conversion before ....just looking for tips... what to look for etc

Paul48

Is there working valves on the radiators? It probably seems like a stupid question, but when you pump those systems, they can make it much easier to balance the system.

Gordy

That is a piping method of slowing down gravity flow. Your assumptions are correct.

Paul S_3

yes valve work ...I may have to change a few 1 inch angled ....but for the most part yes they turn....I couldn't run the system no oil in tank....this is an oil to gas convo.....hopefully this guy can understand the value in my proposals.....company can just go in there for 1/3rd the price and bang out install

Gordy

As far as your offerings have you done, or will you do a radiation survey? How is the owners budget constraints? Has there been envelope upgrades?

Gordy

Paul S said:

yes valve work ...I may have to change a few 1 inch angled ....but for the most part yes they turn....I couldn't run the system no oil in tank

Sometimes a turning valve stem is not an indication it actually functions.

Paul S_3

no EDR survey until deposit is collected.....I agree with the valve testing....just would like to be prepared if they want convo....never done gravity to circulation before

Paul S_3

no envelope upgrades.....plaster lathe walls.....heat loss maybe in the 125K zone...proposal covers even larger if anything

Paul48

It's a huge manifold system. Keep it simple.

Paul S_3

thanks.....guys

Ironman

That's an ideal candidate for a mod/con. No great mystery involved in converting it to forced flow.

Flush, flush, flush with water until it runs clear. That will involve installing purge valves with the new boiler. Use a magnetic strainer to catch what flushing doesn't. The new near boiler piping can be sized by cutting the size of the gravity in half, then go one pipe size smaller. In other words, if it's a 4", then 1/2 of that would be 2" - one size = 1 1/2".

One ups15-58 or equal circ can probably carry everything unless your boiler requires p/s.

Somewhere on here years ago, I posted about 10 things to do on a gravity conversion. A search should locate it. Dan also has some articles about it under the resources tab.

Paul S_3

thanks Bob