Hooking up boiler with storage to propane boiler

[EffectaBoilerUser (USA)]

I will be installing a new Effecta Lambda 35 boiler in my house next week and will be using it with 1000 gallons of storage.

I would like to use it as a full time heat source for my house, DHW and hot tub but want to plumb it so that I can use my propane boiler when I am on vacation. I would like to be able to use the effecta lambda 35 boiler and storage and when the water in the Effecta Lambda boiler/storage gets lower than 135-140F I would like my propane boiler to takeover automatically. I would like this transfer from effecta lambda boiler to gas propane boiler to occur without any manual mechanical or electrical switching and want to make sure that the propane boiler does not heat my 1,000 gallons of storage when it is operating.

I have designed a layout that would use a temperature setpoint controller that would control a 3 way, 24V valve and 2 way, 24V valve. In addition, I would plumb the supply line from the tank to go thru the return side of my boiler, and out the supply, hot side of the propane boiler and to all the zone valves and controllers. I plan to turn the aquastat on the propane boiler itself down to a little less than 135F so that it would never come on as long as the incomming water being heated by the Effecta Lambda boiler is above 135F. The operation would be as such:

1.) Effecta Lambda is providing heat energy to storage tanks and the house is pulling heat off of the tanks to heat the house, DHW and hot tub demands (this water is going thru the return side of the propane boiler and out the supply side of the propane boiler).

2.) Once the water in the storage tank/going to the house gets below 135F the setpoint controller (with a probe in the top of the storage tank) signals a 3 way valve that is on the outgoing, supply side of the propane boiler and a 2 way valve on the line going from the tank to the gas boiler. As long as the temperature of the water going thru the propane boiler is above 135F the 3 way valve will direct the water leaving the propane boiler back to the storage tank/effecta boiler. If this water gets below 135F than the 3 way valve will direct it back to the return side of the propane boiler (and the 2 way valve will prevent it from drawing cold water in from the storage tank) and the propane boiler will fireup and maintain a water temp. of 135F.

I have attached a schematic to this email and welcome any and all comments.

If anyone has another idea for this type of system design please let me know.

Mr. Effecta

 

[Singed Eyebrows]

I will be installing a new Effecta Lambda 35 boiler in my house next week and will be using it with 1000 gallons of storage.

I would like to use it as a full time heat source for my house, DHW and hot tub but want to plumb it so that I can use my propane boiler when I am on vacation. I would like to be able to use the effecta lambda 35 boiler and storage and when the water in the Effecta Lambda boiler/storage gets lower than 135-140F I would like my propane boiler to takeover automatically. I would like this transfer from effecta lambda boiler to gas propane boiler to occur without any manual mechanical or electrical switching and want to make sure that the propane boiler does not heat my 1,000 gallons of storage when it is operating.

I have designed a layout that would use a temperature setpoint controller that would control a 3 way, 24V valve and 2 way, 24V valve. In addition, I would plumb the supply line from the tank to go thru the return side of my boiler, and out the supply, hot side of the propane boiler and to all the zone valves and controllers. I plan to turn the aquastat on the propane boiler itself down to a little less than 135F so that it would never come on as long as the incomming water being heated by the Effecta Lambda boiler is above 135F. The operation would be as such:

1.) Effecta Lambda is providing heat energy to storage tanks and the house is pulling heat off of the tanks to heat the house, DHW and hot tub demands (this water is going thru the return side of the propane boiler and out the supply side of the propane boiler).

2.) Once the water in the storage tank/going to the house gets below 135F the setpoint controller (with a probe in the top of the storage tank) signals a 3 way valve that is on the outgoing, supply side of the propane boiler and a 2 way valve on the line going from the tank to the gas boiler. As long as the temperature of the water going thru the propane boiler is above 135F the 3 way valve will direct the water leaving the propane boiler back to the storage tank/effecta boiler. If this water gets below 135F than the 3 way valve will direct it back to the return side of the propane boiler (and the 2 way valve will prevent it from drawing cold water in from the storage tank) and the propane boiler will fireup and maintain a water temp. of 135F.

I have attached a schematic to this email and welcome any and all comments.

If anyone has another idea for this type of system design please let me know.

Mr. Effecta

Mr Effecta, I can't comment on the system design, others have more experience. Does your boiler have auto light? I had read that these do. This may have been for Sweden only though. I appreciate the time you have spent to help me with my Laddomat problems & look forward to reading about your install, Randy

 

[Hunderliggur]

A lot depends on your actual operating temps. If the return temp is less than the storage tank (tank is warm, but not hot enough to heat) you may want to preheat the return before going to the boiler. If you three way at the boiler you can route to boiler if less than operating temp (135) or direct to supply if greater than 135. You may need a mixing valve at the storage tank if storage is much greater than 135 (my bamboo floors and radiant heat would not like that). So in short, thwo differential controllersand 2 3 ways - 1 to control storage use (if stoage > return, use it) and boiler use (if storage supply < 135, boost it in the boiler).