zapps
New Member
I'm looking to replace my Rinnai tankless water heater that is used for hydronic heating (w/ wall-mount convectors) and domestic hot water. The system is open-loop so I want to use this opportunity to make it close-loop as well.
Most of the contractors that came to estimate propose Navien combi boiler. Reading through this forums and research on the internet however suggests that this would cause short cycling on the space heating side due to the heat load of individual heating zone is a lot lower than the combi boiler minimum btu.
One contractor argues that short cycling can be avoided by using primary/secondary piping (or pumping) configuration. He tries to explain it to me but I still don't get it. So I'm here looking for help. Is it true that there is some piping magic that can remedy short cycling issue with using combi boiler?
Some addition background info: It's a 1,800 sq.ft. townhome in Seattle. Heating is devided into 5 zones, each has one wall-mount convector (rated at around 5000 BTU based on its spec sheet).
Most of the contractors that came to estimate propose Navien combi boiler. Reading through this forums and research on the internet however suggests that this would cause short cycling on the space heating side due to the heat load of individual heating zone is a lot lower than the combi boiler minimum btu.
One contractor argues that short cycling can be avoided by using primary/secondary piping (or pumping) configuration. He tries to explain it to me but I still don't get it. So I'm here looking for help. Is it true that there is some piping magic that can remedy short cycling issue with using combi boiler?
Some addition background info: It's a 1,800 sq.ft. townhome in Seattle. Heating is devided into 5 zones, each has one wall-mount convector (rated at around 5000 BTU based on its spec sheet).
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