Munchkin Boiler And DHW Indirect Tank

clammy

what was the heat lose for the home i know the first stage or low fire i guess is larger then your hydro air coil maybe just run your primary loop through a buffer tank with a coil and use that as a domestic pre heat.Can you post a pic of the piping or may be a diagram peace and good luck clammy

TXVsRule

Munchkin Boiler And Indirect Tank

I have an existing installation of a Munchkin 199M with Vision1 controlling 3 zones of hydro-air handlers. The system is piped as per Vision 1 standards.The homeowner now wants to add an SS80 indirect DHW tank. I would also like to see this tank act as a buffer tank as well, helping to cut down on some of the cycling. Does it make sense to pipe the tank coil in the primary loop so that when the primary circ runs it uses the tank coil to stabilize the boiler temperature. When there is a call for DHW heating the primary circ could start and heat the DHW tank. There are secondary circs on each zone so they would only start with the zones t'stats. A mixing valve would take care of the much too hot DHW temps.

Thoughts anyone?

Rob

clammy

vision one

I believe that with the vision one and a indirect that your primary pump will not run you would have to add a second pump as per vision one piping because the primary pump will not run for heat if it is on warm weather shut down .I think i would get a tank in tank and use it as a pre heat for your domestic off your primary loop and pipe it into your indirect as yor cold feed and add a mixing valve to yor indirect tanks outlet temper the water to desired water temp .I have a few munchkin in and i've yet to have any short cycling promblems mostly the burner will modulate down unless the heat lose is below the lowest burner modulation a seperate buffer might help ,also if your are using the vision one indirect sensor remenber to set the pre and post circulator run other wise you will have a hard lock out on hi temp sensor on the munchkin ask me how i know peace and good luck clammy

TXVsRule

Problem is this, there is 1 zone that has a small variable speed air handler w/ water coil. When this zone runs alone at low fan speed the Munchkins lowest fire is still too high and it short cycles, though not too badly. This is why I figured on killing two birds with one stone. I was going to set up the Vision wiring so that if either the Primary or DHW pump was calling it would run the primary pump that would be looped through the DHW tank coil. I suppose I could just add buffer tank in addition to the DHW tank.

Rob

Guy_6

A thought

Do you have the differential on the Munchkin set to 30 (the widest diff)?
What would be the effect of putting a SMALLER circ. on that little air handler? Would a slower flow through that zone still give you the necessary heat while cooling the return water more? That would put a somewhat larger delta to the boiler, giving longer run times.

TXVsRule

If I slow the circulator down too much the air temperature goes way down. It doesn't make any heat but the boiler stops short cycling.

Clammy,
I think I am going to use a small buffer tank with a coil and a triangle tank for DHW. This will stop the short cycling and preheat the DHW.

Thanks,
Rob