p/s or boiler bypass

j a_2

Many of my boiler replacement jobs involve older twice converted gravity systyems with some very interesting additions...I begin by figuring out supply and return piping then cutting everythig out....My question is this for a non mod con boiler what near boiler piping do you think is best for the boiler and venting systems, installing a boiler bypass as described in most installation manuals or piping a form of p/s piping. I have always used a bypass but most recently have been installig mod cons using p/s piping and I like it..What do you think thanks

don_205

Modcon

Modcon has no issue when it comes to low water temps other then they like them.

Primary/sec piping is not to protect the boiler from low water temps,it to maintain proper flow thru the boiler.

j a_2

Don are you saying p/s will not protect a cast iron boiler from low water return? My question is ,what system of piping do you think is best,either one will work wont it

Unknown

P/S

P/S piping(2 pumps) will provide the proper flow through the system-side, while the other pump provides through the boiler, allowing hydraulic separation of the 2 sides.
However, that alone will not guarantee CI boiler return protection.
For an inexpensive solution I typically use these on CI boiler installs.

Dave

Unknown

J A

Most of the boilers I do are the same in this city, Reading PA. Old gravitys originally in coal then converted to oil or gas. First mistake that is usually done on these systems is noone ever reverses the returns so there is tremendous flow imbalance in the systems, second, which compounds the problem is most guys install a system bypass not a boiler bypass, The reason for that is because before Dan changed the way boiler companies shipped their boilers they had the pump mounted on the return already, which meant you would have had to remove the pump and place4d your T under the pump to properly install a boiler bypass. Hmmm thats almost as much work as reversing the returns. So it was easier just to put a T on the supply and bypass into the inlet side of the pump. Ta Da system bypass installed! Which meant even less flow for the imbalanced system. Usually somewhere, someone came in to help the customer find out why there was no heat in the farthest radiators. Ahh there it is, all we have to do is shut this bypass and more water will go to the rads... close but no cigar. Anyway thats how they sit for 40, 50, 60 years. Oh yea I know all about the flue gas condensation thing and I have been doing this now for 30 years but I think our city is immune to this disease and the Ray boiler doesnt seem to mind. Anyway a P/S WLL "protect" the boiler, just set the flow rate through the boiler slower than it can disipate so it comes up to temp, I would imagine the boiler should come up to temp in 15 minutes or so but I have never got a good answer on this. Some of these manufacturers should just can the theroretical BS and try to figure out how to tap a straight thread in thier castings!

Unknown

I agree to a point Tony,

it sounds like you`re describing a simple manual bypass which may be fine for a 1 zone system.
If there are 2 or more, the flow requirements will change and boiler could be bombarded with cool return water for a longer duration.
I believe getting-up above condensing temp faster than 15 min. is better, and easily accomplished with P/S & this thermic valve, especially if it were oil-fired. JMO.

Dave

Unknown

Dont forget J A

The federal tax credit on condensing boilers is now 30% with $1500 cap. Most have built in low water cutoff and dont need the thermostatic protection. Along with the savings in fuel there is very little reason to sell anything but modcon.

[Deleted User]

Dan changed the way boiler companies

shipped their boilers? to stop the 'mistake' of pumping
'to'? maybe on CIs but not mods as you're well aware. weil and munch to name two, leave circ unattached, and want it attached pumping 'to' as per their piping diagrams

Unknown

mike

I think you & Tony could start WW 3 if you wanted to.
Tony was describing a CI replacement boiler(circulated), to a gravity circulation situation.
His applications seemed to have worked for them,, but perhaps not all.
I enjoy his input,, M/C`s aside.

Dave

Unknown

Yes he did

When Dan wrote the book "pumping away" there were no mod cons and all cast iron boilers came with the pump mounted on the return. As a matter od fact Weil Mclain used a piece of preformed steel pipe with a flange already on it. After a while they stopped mounting the pump and extended the bx cable. I was guilty of the same type of pump placement because I never really thought about it nor really understood it. I just did what I was taught. I believe the munchkin was the first modcon available here. If I remember correctly I believe Mark Eatherton was one of the first to get one, we were posting here one evening and I remember Mark being all excited about a boiler he was getting by UPS. Dan not only changed the way boiler companies shipped thier boilers, he changed the way I look at heating systems and has taught me to use MY MINDS EYE. He has put alot of money in my pocket, far more than he charged me for his schools or books. My father teaches the third year plumbing apprentices here and Several of Dans books are thier standard text.

Andrew Hagen_2

PONPC

I'm not sure if I am reading this right, but it seems like it's worth saying that "pumping away" refers to pumping away from the expansion tank. In general, there is nothing wrong with having the boiler on the discharge side of the circulator.

scrook_3

but...

from an air elimination point of view you want that lowest pressure (circulator inlet) point to also be the hottest point, as this is the point of lowest air solubility in the water, so this, combined with the desire to have the circulator pump away from the PONPC, leads to the X-tank and circulator inlet(s) wanting to be connected to the outlet side of the boiler.

[Deleted User]

ww3? naaaaw

i have all of dans books, and if you read them closely, he doesn't really claim all that, and he readily cites that he got the pumping away idea mostly from gil carlson, but also from others. and as far as the shipping issue, i'd lay money on it that boilers were piped with the circ pumping 'to' the boiler before manufacturers started putting them there, bec i'm quite sure that that my childhood home, 40's, did not have it's boiler shipped with it's pump where it was located, bec it would have been impractical packaging

[Deleted User]

yeah i know andrew

and that's why i put the 'marks' around the 'to', so as not to indicate the ponpc 'away' idea. and dan even has a couple examples of the 'to' that i was refering to in his 'hyd rad heat' book

Unknown

Sheesh

I understand what Andrew & Scrook are saying,,,,
But I`m in the dark about this "mike" guy things, did I miss something?

Dave

joe_94

With Esbe TV , pump only on return?

Can the Esbe/Danfoss only be used where the circulator is on the return to the boiler?

Unknown

Not really joe,

just read the leaflet, you`ll see.

Dave

[Deleted User]

miss something?

you're not alone. i have an abreviated/peculiar way of writing bec i'm a man of few words

Unknown

Few Words mike?

How can you expect help, or any ideas to a prob, if you say next-to nothing?

Dave

[Deleted User]

dan's examples

have it on the return or supply, with different results for each, but in both examples, the circ is on the return/ pumping 'to'

scrook_3

He's...

saying (with some expansion on my part): Dan's said Gil Carlson of B&G pointed him to the "pumping away" concept that Carlson had published in the '60's, and that conventional practice in the 1930's (thru at least the '90's, and even to present on some mod/cons) was to place the circ. on the return (though w/ the X-tant at the circ inlet, hence "pumping away"?

On older converted gravity systems with low system heads & low flow rates it probably didn't matter much if the circ pumped toward the X-tank, also the seals on the circulators of the day may have been happier w/ somewhat lower water temperatures regardless of whether the x-tank was on the circ inlet or the boiler outlet.

Alas, habits & conventional wisdom die hard.

[Deleted User]

dave, i wasn't asking a question

but when i do, i have enough sense to make it as clear as possible without overusage/rambling, or i use many individual, short-worded questions

[Deleted User]

with some expansion?

as in a tank joke?

i did my first stable-up/away system on my house 10ish yrs ago and it works perfectly. i bleed very little when i drain and refill

Unknown

???

OOOOO-k-aaaa-yyyyy,,, I guess,, LOL.

Dave

[Deleted User]

dave

what, you didn't 'get' my funny take on your line; "He's...saying (with some expansion on my part):'