Review simple electric boiler layout

[slackdaddy1]

Getting ready to sweat the mechanicals up and was looking for any input before I do. See attached sketch.
It is a closed system with 2 - 300' loops.
I placed the fill and purge connections as the highest point, so when pumping in the antifreeze solution it would be easier to purge the air.
I also located the boiler low on the wall so it is NOT the highest point of the system, so it will not run dry.

Did I miss anything?

Thanks for any comments, good or bad.
Slack

 

[bobbyjean]

looks good...the boiler itself has no tapping for a relief?...usually you dont want any valve's between a safety device...so the oem gives a tap for it...the expansion tank is a similar deal(no valve) ....as long as you keep it mind...
Can you do a pressure test before filling? alway's a good idea

 

[bobbyjean]

Sorry...just checked on the boiler online...that thing is small..no wonder there is no extra tap for relief...didnt read the manual but would you know if they have a low water or a flow switch?

 

[slackdaddy1]

Bobby,
thanks for the response.
There is zero mention of any built in, or any need for an external low water cut off.

The slab PEX has held pressure for over a year.

A flow switch would not work tied in series with the T-stat, as it wont sense flow until there is a heat call and the water is moving.

Guess I'll email the manufacture.

Slack

 

[bobbyjean]

i read some of their manual -they use both auto and manual reset limit controls...no mention of need for low water/flow switch...you can install one and wire it thru thermostat if you wanted.
the unit has a 30 second delay to energize first stage heating element after initial call-so pump is moving water for that time period...temp control then is staging elements
what type of thermostat will you use?....i see that slab stats are mentioned

 

[slackdaddy1]

Bobby,
I am using a simple air T-stat.
In the manual it states that if the tubes are in the slab (not under) and there is no floor covering than slab sensing is not needed.
This is a simple700 sq ft garage, plan on keeping the air temp at about 50 deg F.

 

[bobbyjean]

so... you should be all set...if you wanted you can leave a 1 inch tap in pipe at a safe water level for boiler....for a lwco later....check out gaurd dog mini...it's a 3/4 thread..but good practice to go larger in pipe with a bushing.....happy heating

 

[roscoe2000]

I would add a temp gauge on the boiler outlet unless one is included with the internal boiler controls. Since your use is for low temp (slab heating) my suggestion is more for trouble shooting/verifying output matches requirement.