Poor soul undersized boiler

mike faust

It is piped primary secondary. 007 on secondary side. Primary I'm not sure of the size. I believe a grundfoss u-15...does that sound correct...dunno. An old weil Mclain cast iron boiler is what we pulled out. Not sure if it was originally gravity, but the house is older than 100 years and i'm sure the weil Mac was not original

mike faust

Sizing issue

Please remember I am basically a green horn to hydronic heating. As always I am extremely eager and open to learn. The bad thing is I'm really into the "READY, FIRE AIM, METHOD" of doing things.

Just pt in a laars max low mass boiler. Primary/secondary piped to cast iron radiator system. Ran it for one hour. On start up return 75f--supply 97f. It took one hour to come up to 135f return and 160f supply. I put a temporary by- pass in to help with any condensing. Should i use a thermic valve? Would an outdoor reset control help...If so how?

radioconnection_2

boiler sizing

Did you do a heat loss? How did you size the boiler to the house?

The TV valve will help maintain the return temperature to protect a boiler; if it is needed.

martin

Return temp control

you will nrdd some sort of mixing valve to keep return temps in 140 range to control condensation.

mike faust

sizing

Rhvac load calculation. sensible lss of around 85,000btu...but I don't have the exact number with me. For the rads I used a chart my local supply house gave me on sizing...

mike faust

return temps

Do you think my circ sizing is off on the secondary side. A smaller circ would perhaps allow more gph to travel through common piping directly back to boiler???? What do you think?

kevin coppinger_4

lets start...

again...Is this gravity conversion system? Big pipes...what was there before. I might think about doing some sort of injection control w/ built in protection...a 4 way valve would work great....got pict.? kpc
ps..just saw your other post...what circ sixe is on the system?

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mike faust

4 way valve

How does a 4 way valve work...?

kevin coppinger_4

try this..



this is 1 model...kpc

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Timco

Let's step back. First, a heatloss calc will size the boiler. Assuming you have enough btu's in the boiler you put in, a 007 or a grundfos 15-58 will typically run a 11/4" primary loop with a thermic valve. I ALWAYS use a TV with copper-fin boilers. The laars will heat the pri circ very quickly, and the heat will bleed into the secondaries from there when the TV opens @ 140* if placed on the return. This works well on CI rad conversions I have found. What we need are pictures of the near boiler piping to know if you piped the secondaries correctly off the primary circuit. If you did it wrong, the Laars will not last long as they do not like abuse.

mike faust

Tim

I will get some pics tommorow. The T--spacing on the secondary loop is roughly 7". The primary circ is piped 16" down line of the boiler supply assembly. In the assembly I have the old expansion tank connected to the top and the fresh water fill into the side before the cirulator. There is no diaghram type tank. The water seems to be traveling through the secondary loop leaving the "common piping" between the tees cool or "neutral flow" or so it seems to me.... again I am a newbie!! Thanks for your help so far.

Timco

These pictures are P/S piped boilers with a TV. The unfinished one was a laars. Note the closley spaced tee's off of the primary loop. The top one is supply, and the second is return. Always tap off the pri loop with close spaced tee's. The fill goes into the pipe that leads to the x-tank. I think I can find a picture of it. Always pump away from the x-tank with the pri circ.

Tim

mike faust

tim

The boiler is a laars max 120. I'll do a heat load on the home tommorow but i'm sure it was less than 100mbtu

Paul B._2

Laars Max

Hi Mike,

I too am interested in seeing a piping diagram for this installation.

Is the boiler operating for the full hour, non-stop, or do we have a short cycling problem here that is causing the boiler to not meet the load demand.

Please put together a drawing, and fax it to me at 603-335-5212, and include your daytime contact information.

I can be contacted at 603-335-6300 X 562.

Sincerely,

Paul Bock, Applications Engineer, Laars Heating Systems.

mike faust

Sorry bout the multiple threads

Sorry bout the multiple threads. This is one of my first times using the "wall", Just getting the hang of it. This was from above:
I will get some pics tommorow. The T--spacing on the secondary loop is roughly 7". The primary circ is piped 16" down line of the boiler supply assembly. In the assembly I have the old expansion tank connected to the top and the fresh water fill into the side before the cirulator. There is no diaghram type tank. The water seems to be traveling through the secondary loop leaving the "common piping" between the tees cool or "neutral flow" or so it seems to me.... again I am a newbie!! Thanks for your help so far.

mike faust

Paul, Laars Max

It is running the entire hour. After researching tonight I do believe I simply need a TV to increase return temp. It seems the realproblem is boiler condensation from low return water temperatures. Pictures to follow tommorow. Thanks, good evening!

Ross_7

Air separator

If you're using an automatic air separator, or any other auto air vents, then you should be using a diaphragm style expansion tank, not an open steel expansion tank.

mike faust