efm 520 bypass loop

Re: efm 520 bypass loop

PostBy: gaw On: Thu Nov 22, 2007 10:03 am

Getting back to the original question. On EFM's that I am familiar with and that have been "professionally" installed they have a valve in the bypass loop and a valve in the return line. On boilers with circulators mounted on the return this valve is between the ciculator and the T for the bypass. These are usually gate valves but probably do not HAVE to be. The purpose was to control the rate of flow. You don't want to have your boiler cool down fast and then turn off the circulator until it recovers, you would prefer a loss of maybe 10* during a call for heat and keep the circulator running during stoker operation.

Now to the off topic, and this is not for you ted as I see you are well on your way. On my "old school" boiler that I plumbed up "old school" in an old house (old is becoming a recurring theme and is getting old) the outlet on the top of the boiler had a drop tube welded under the pipe tapping.This extended about an inch into the top of the boiler. An "old school" steel expansion tank was attached directly to the top of the boiler via 1" pipe with a stop waste valve in between. The way they handled air was to trap it in the top of the boiler and purge it into the expansion tank. I am not an expert nor did I sleep at a Holiday Inn Express last night but it appears to me that handling system air is a total system approach more than just pump placement. Follow a proven system design and don't mix and match between multiple approaches. Thats my opinion, that will be 2 cents please.
gaw
 
Stoker Coal Boiler: Keystoker KA-6
Coal Size/Type: Rice from Schuylkill County

Re: efm 520 bypass loop

PostBy: stoker-man On: Fri Nov 23, 2007 8:58 am

A standard installation will include expensive circulator pump isolation flanges


I think one of the reasons for efm not putting circulators on the supply side was because the outlet of a 520 boiler is 3" and the largest flange we handled was 1 1/2". I will ask about this issue and get back to you.

ISO flanges are cheap. When you consider that replacing a pump without draining and bleeding the system is a 10 minute process, the $50 cost (?) is worth it. I have ISO and ball valves everywhere I would need to ever work on my system.

Another reason for the bypass loop is that you can force some of the cooler water back into the supply line to moderate the heat to the radiators for longer runs on a single loop system, where the tstat might be in the first room. I think the boiler holds 39 gallons of water, so it also moderates the whole boiler.
stoker-man
 
Hand Fed Coal Boiler: 1981 efm wcb-24 in use 365 days a year
Coal Size/Type: Anthracite/Chestnut
Other Heating: Hearthstone wood stove

Re: efm 520 bypass loop

PostBy: gaw On: Fri Nov 23, 2007 10:43 am

stoker-man wrote:Another reason for the bypass loop is that you can force some of the cooler water back into the supply line to moderate the heat to the radiators for longer runs on a single loop system, where the tstat might be in the first room. I think the boiler holds 39 gallons of water, so it also moderates the whole boiler.

I agree. In an old house with big iron radiators you would probably cut the circulator off after getting one or two radiators hot then the boiler has to recover and the first in line radiators get the hot water again when the circulator restarts. Most old houses that have an old system in place are on ONE heating zone. In an old house with a single heating zone you would want to keep that circulator running continuously and bring the radiators or baseboard up to temperature gradually throughout the house for a more even heat.
gaw
 
Stoker Coal Boiler: Keystoker KA-6
Coal Size/Type: Rice from Schuylkill County


Re: efm 520 bypass loop

PostBy: huntabsarokee On: Tue Jul 01, 2008 10:02 am

Yanche

Thanks for the PDF file that you posted. I think that will help a lot of the DYI on here including me. I plan to use it to guide me through my KA-6 install rather than diagram supplied by Keystoker which has the circulators on the return side. I do have a few questions maybe you can help me out with.
1) What is a hose drain? Is it simply a gate valve with hose thread and will it only be used to get rid of O2 as you described when filling the boiler?
2) I need to put a bypass loop in and will install in the loop a 4006B safety control that comes with the boiler. Should the by pass loop go after valve A and before the air separator or after the separator or doesn't it matter?
3) Is it normal to split the water supply/fill line where part goes to the expansion tank and the other goes directly to the boiler for a faster fill? I plan on installing the Amtrol expansion tank with the Fill-Trol valve.

Thanks in advance for any input!
huntabsarokee
 
Stove/Furnace Make: Lopi - Keystoker
Stove/Furnace Model: Reveere Wood - KA6 dual fuel

Re: efm 520 bypass loop

PostBy: Yanche On: Tue Jul 01, 2008 6:59 pm

Answers:

1. A hose drain also called a boiler drain. It's a globe valve with an angled male hose thread connection. An ordinary ball, globe or gate valve and a male hose thread adapter will be fine. Be sure to pipe it so that trapped air bubbles will be able to get out the valve. Usually means the valve is on the top of the supply line before valve A.

2. I'm not sure I understand what you are suggesting because I'm not familiar with a efm 520 bypass install. In any event the bypass should be before valve A, i.e. between the valve and the boiler supply tapping. If you are suggesting using the 4006B immersion well as port for the bypass piping. I'm not sure that's a good idea. I'd defer to others with more experience with efm installs. I'm concerned about where you might re-locate the immersion well and if it's a suitable location.

3. Yes you want a fast fill water path that by passes the water fill regulator. Without one it will take a long time for the initial water fill and the initial air purge will be only marginally effective.
Yanche
 
Stoker Coal Boiler: Alternate Heating Systems S-130
Coal Size/Type: Anthracite Pea

Re: efm 520 bypass loop

PostBy: huntabsarokee On: Tue Jul 01, 2008 8:26 pm

Well I am not installing a EFM but a Keystoker but Keystoker's drawing has a bypass loop too. On their drawing the supply comes out the top of the boiler, then a Tee where 1 end is for the by pass loop the other goes to the radiators, then on the by pass loop there is another Tee and on the end of that Tee the 4006B is installed to monitor the water high temp and of course the other side of the Tee continues on to the return side of the boiler.

I think its just a basic by pass loop but on the loop they add a TEE for the 4006B to monitor high temp as safety measure. Sorry if I didn't describe it very well but the drawing is at my work right now.
huntabsarokee
 
Stove/Furnace Make: Lopi - Keystoker
Stove/Furnace Model: Reveere Wood - KA6 dual fuel

Re: efm 520 bypass loop

PostBy: Scottscoaled On: Tue Jul 01, 2008 10:10 pm

Nice job Ted. Looks good! When are you running for a load. :) Scott
Scottscoaled
 
Stoker Coal Boiler: EFM 520x4, 350, 700. Van Wert 400 x 2, 800, 1200.
Coal Size/Type: Lots of buck