Hello, I'm replacing my old ineffiecient boiler with a newer hi efficiency boiler with domestic water heating.

Does anyone here have a diagram of a bypass line and valve setup?  What exactly is the bypass function and how is it adjusted for optimum efficiency?

Your experience is greatly appreciated.

Vic

What kind of problems did you run into TT?  

The boiler I've purchased is a high quality unit that has proven itself over the course of two years of operation.

I bought it used.  The reason it is used is because the person that owned it passed away, then her house was torn down, but, the boiler was salvaged because it was so new.

The factory is aware of how I purchased it and will stand behind the warranty.

Basically all I need is an accurate plumbing diagram so that I can properly incorporate the bypass system. My current boiler does not have a bypass installed I would imagine due to its age.

Vic

In the paprework it does recommend a bypass so that 160 degrees F. will be maintained in the boiler for domestic water supply and so that the technician can be assured of the return water temperature.

None of my baseboard heaters have a valve to turn them off like the radiator types do. Possibly I do not need a bypass on this type of system.

Vic

Possibly, but, here I'm just talking theory and not actually installing it.

Vic

by baseboard do you mean warm air heaters?

if there are no valves and no means of isolating it, it sounds like its already a 'big' bypass all on its own. One pipe system.

[quote author=Victorious1_1  link=1101318798/0#11 date=1101337200]Therefore in essence, if the Lo setting is 160 degrees F. the return water should always be essentially 160 F. because it is in a continuous bypass pattern, correct?

If this setup did not prove to maintain the return water temp. at 160 F., then I would have to regulate return water temperature by using the circulating pump?

Thanks for your experience and knowledge.

Vic
[/quote]

Not correct the return will be lower depending on the heatloss which is quite a bit with finned rads.

but then you want it to be lower anyway.

scruff

I wouldn't have thought you'd be able to achieve this - simple laws of physics dictate that you will inevitably encounter and accumalate losses - heat or otherwise, from the start to the end of the system.
Unless you have something along the lines of a perpetual motion machine which is totally free of losses of any kind!

Whatever means you have to provide heating to the rooms will inevitably give up heat to atmosphere as the hot water circulates, so you'd have to begin by delivering the heated water at a lot higher temperature than the temp you eventually wish to achieve on the return.

So there is a clue to your starting point.
Insulation, plus a larger boiler possibly?

One for a REAL heating engineer methinks.
Though I cannot understand why you need to dictate the fact that the 167' value HAS to be maintained?

TT

you will need to regulate the flow by cutting in valves to the feeds to the baseboard [skirting heaters] to regulate the temp across the heaters.would be more cost effective to alter to a two pipe sys and incorperate a abv to maintain the temp difference

scruff, it's an NY Thermal, Legacy L-150 boiler.


Bripl, why do you say that it would be more cost effective to convert to a two pipe system?  Isn't the bypass simply a matter of a couple of T's and a bypass valve?

Vic

Vic, There's something amiss here.

Assuming that this is a Condensing Boiler, I don't understand why it requires the return water temperature to be a MINIMUM of 160 degrees F.

Condensing boilers usually require a LOW return water temperature which facilitates the condensation of the flue gases on the cold return water end of the Heat exchanger.

In DHW mode, the primary circuit is diverted through the DHW Heat exchanger so maling the temperature of the return from the Heating Circuit irrelevant.

The Bypass is usually used to maintain some circulation through the Primary Heat Exchanger when the heating zone valves ot TRV's shut down so that the water doesn't boil in the Primary Heat Exchanger.

So sorry guys, I should have stated up front that this boiler is Canadian made for use here in Canada.


The reason the manufacturer wants the return temp. maintained at 160 F. is to prolong life of the steel boiler and to be able to provide hot water thru the domestic tankless coil in the boiler.

So, now that I'm being understood clearly, does anyone have a plumbing diagram or link that would illustrate how the bypass would best be piped?

Vic

Thanks a lot guys, especially you scruff, very much appreciated.  I'll let you know how it all works out in the end.

Vic

You've got mail scruff, thank you.

Vic