Rebuild My EFM 520

dave28 · Post by **dave28** » Sun. Nov. 27, 2016 10:47 am

Rob R. wrote:
Nope.

That radiant slab will really suck some heat. There are a few things you can do to reduce the "shock" on the EFM.

1. Turn down the temperature of the water going through the floor via the mixing valve. 100F is probably plenty.
2. Adjust the bypass valve(s) on the EFM to reduce the amount of cold water being returned to the boiler.
3. Increase the feed rate on the stoker. 3 teeth is too low to do much of anything. 4 is the minimum for most applications, and 5 will noticeably reduce the recovery time.

I would start by adjusting the mixing valve, and increasing the feed rate. You already have it piped primary secondary, so returning really cold water to the boiler should not be a problem. I suspect the floor just sucked all the heat out of the boiler and the feed rate was too low for it to recover in a reasonable amount of time.

Rob,

I think you are right that the floor sucked all the heat out of the boiler. I hadn't even thought about adjusting the mixing valve down, good call. I was trying to adjust the Tstat for the floor but it is such a pain to program. I think I'll get the wife to do that, she does good with those. I checked the floor temp and it's runing mid to upper 70s. I'll bump the feed up some and adjust the bypass and see where that gets me.

Post by **Rob R.** » Sun. Nov. 27, 2016 11:11 am

How warm do you keep the garage?

There is no shame in going back to a round Honeywell thermostat.

dave28 · Post by **dave28** » Sun. Nov. 27, 2016 11:34 am

Thermometer says the air temp is 66° but I'm not convinced it's 100% accurate. Floor temp says mid 70's. I may have to consider the old round Tstat. I had this one laying around from the old oil furnace so I figured I'd use it. I noticed last year that keeping the garage floor warm helps keep the upstairs warmer and I used a lot less fuel oil last year.

dave28 · Post by **dave28** » Thu. Dec. 15, 2016 12:24 pm

I am really enjoying the heat from my 520. I'd like to thank everyone on the forum that gave me tips and advice and through trail and error it is finally running as I thought it should. Right now it is 12° with a wind chill of -4°. Temp inside the shed is holding at 68°. I finally got the building insulated and now all I need to do is get insulation on the pipes. I'm getting around 2/3's of a tub of ash in 24 hours.

I'm going to miss this heat tonight while I'm moving locomotives in and out of the shop tonight with temps around 0° and wind chills below that.

Thanks,
Dave

Post by **StokerDon** » Thu. Dec. 15, 2016 7:12 pm

dave28 wrote:I am really enjoying the heat from my 520. I'd like to thank everyone on the forum that gave me tips and advice and through trail and error it is finally running as I thought it should. Right now it is 12° with a wind chill of -4°. Temp inside the shed is holding at 68°. I finally got the building insulated and now all I need to do is get insulation on the pipes. I'm getting around 2/3's of a tub of ash in 24 hours.

I'm going to miss this heat tonight while I'm moving locomotives in and out of the shop tonight with temps around 0° and wind chills below that.

Thanks,
Dave

You will be warm when you get home though!

Glad to hear your boiler is running like it should. We were all a little worried for a while.

-Don

dave28 · Post by **dave28** » Sat. Dec. 17, 2016 7:27 am

StokerDon wrote: You will be warm when you get home though!

Glad to hear your boiler is running like it should. We were all a little worried for a while.

-Don

It has been working a little harder with the wind chills below zero but no problem maintaining the house at 72°.