[j123jam]

I'm moving into a Seattle townhome built in 2005. It has a hydronic heating system with wall fan units, and separate thermostats (the simple knob kind) in each room.

It seems that the thermostats control the actual fans in the wall vents, but they don't seem to turn the water pump on/off. As far as I can tell there's only one pump rather than a pump for each zone as I've usually heard about. As far as I can tell the pump runs continuously and the house gets hot from the radiant heat of the tubes, even with all of the thermostats/fans turned off.

Is there supposed to be a thermostat that controls the pump? Today I flipped the circuit breaker to turn off the pump because it got too hot in the house. It seems very inefficient to keep it pumping water all the time.

I've attached a photo of the system in the garage and the pump. You can see the many lines which appear to have individual manual valves.

 

[user_12345a]

It sounds like the system was designed that way.

Having the pump run all the time may not be such a big deal.

The boiler is probably keeping the water hot all the time; it may possible to set it up so the boiler only starts heating the water with a demand for heat or the pump to only start.

Either way, if you don't have continuous pump operation and continuous boiler operation, it will take a while to get heat - fan coils blowing cold for several minutes b4 u get heat.

The loop is engineered in a certain way and you can't just modify it.

 

[jimn]

The way it's designed. Most multi zoned systems font have multiple circulators. You just use valves for each zone, as long as any zone is calling for heat, he circulator will run. In your case it may be designed to run all the time. Nothing to do here unless you aren't getting heat some somewhere or some room is getting heat all the time regardless of a the thermostat setting. Nothing to do here.

 

[supers05]

A boiler control can be used to turn the boiler and pump on/off with a call for heating at any zone. You'd have to run wire to each zone from the boiler area.

A boiler reset control (usually integrated with a zone controller) can control the temperature so that when it's not so cold outside, you don't overheat your house like you mentioned. Unfortunately, it looks like all of the heat comes from a single hot water tank that also heats your tap water(dhw). This means that you have little choice over tank temperature.

You could try turning the tank down to 130*F. You shouldn't go lower then that, with that mixing valve no higher then 120*F. You'll have to turn it back up during cold spells in the winter.

Cheers!

 

[j123jam]

Thanks supers05, jimn01, and user_12345a! This is my first post on DIY Chatroom and it's really great to have so much help so quickly

It sounds like I will need to spend $$$ on a professional if I want to upgrade the system. For now I will try turning down the hot water temp and using the circuit breaker to shut off the pump. I bet it wouldn't be too hard to add a timer to the circuit so that I could at least keep it from running all the time.

Followup question: Can I turn off the valves to certain zones of the house (those little metal valves on each tube), or is the pump calibrated for pumping with all of the valves open? I'm hoping I can at least limit which rooms are getting hot water pumped in.

 

[beenthere]

Is that water heater providing the how water for your heat.

 

[j123jam]

Yes, that heater supplies domestic hot water as well as heating the hydronic system.

 

[user_12345a]

If you had a boiler could get an outdoor reset which turns the water temp down as it gets warmer.

 

[supers05]

You can fairly safely shut those valves. Leave at least one open.

Note: Bacteria and other pathogens can grow in water below 120*F. This is probably why the pump was setup this way. As long as your tank is above 130*F and you wait 15min after opening a loop, before using the hot water, you should be fine. (Eg. Legionella will be more then 99% destroyed in less than 5 min in 130*F water)

That is what I'll probably do when I add heat zones to my hot water tank.

Cheers!

 

[user_12345a]

Can't recommend ever from drinking dhw - for showering/bathing you don't have to worry unless you're elderly or have a weak immune system.

wouldn't worry too much about that.

You can fairly safely shut those valves. Leave at least one open.

Are most pumps like centrifugal fans where the amperage draw drops as the head pressure increases?

Can get in trouble with pump motors if it's the other way around.

 

[supers05]

...Are most pumps like centrifugal fans where the amperage draw drops as the head pressure increases?....

That's a centrifugal type impellor in the picture.

.
...
wouldn't worry too much about that.....

If we didn't have to worry, there wouldn't be laws that govern those temperatures and devices. Even in Ontario, where you are. Those numbers aren't arbitrary, they are actual code requirements here. (Slight rounding on the conversation to Fahrenheit)



Cheers!

 

[j123jam]

I wanted to provide a quick update as I've moved in and played with the system a bit more. The pump doesn't run all the time now. It runs constantly if any one of the thermostats is "on." One thermostat was just barely on (set to the lowest temp possible), and that caused the pump to circulate.

However, it's still a terribly designed system. For example, if the only thermostat that is not "off" is set to 60 degrees and it's 70 degrees in the room, there is no reason for the pump to run. The fan isn't blowing, but there is still heat radiating from the vents and floors, which is a waste and causes the house to get too warm. This is especially dumb when it's cold at night and warm during the day. At some point in the future I might talk to a pro about improving this.

I have lowered the temp in the water heater so that at least the amount of heat it puts off is less when pumping. The water heater was set almost as high as it would go, with a mixing valve (anti-scald) keeping the temp at the faucets close to 130 degrees.

I'm also hoping to discover which valves go to which room so I can turn off the ones I don't need.

Thanks again for all of the responses!
Josh

 

[codemandeals]

Please share any useful info you find, I am struggling with the same system.

I wanted to provide a quick update as I've moved in and played with the system a bit more. The pump doesn't run all the time now. It runs constantly if any one of the thermostats is "on." One thermostat was just barely on (set to the lowest temp possible), and that caused the pump to circulate.

However, it's still a terribly designed system. For example, if the only thermostat that is not "off" is set to 60 degrees and it's 70 degrees in the room, there is no reason for the pump to run. The fan isn't blowing, but there is still heat radiating from the vents and floors, which is a waste and causes the house to get too warm. This is especially dumb when it's cold at night and warm during the day. At some point in the future I might talk to a pro about improving this.

I have lowered the temp in the water heater so that at least the amount of heat it puts off is less when pumping. The water heater was set almost as high as it would go, with a mixing valve (anti-scald) keeping the temp at the faucets close to 130 degrees.

I'm also hoping to discover which valves go to which room so I can turn off the ones I don't need.

Thanks again for all of the responses!
Josh

 

[j123jam]

Sorry codemandeals, I haven't found any solutions. I do wonder if an electronic thermostat like this one would make a difference:

https://www.amazon.com/dp/B00H6ARNXO/

I doubt it, but it doesn't seem feasible to change out the single pump for multiple pumps, at least as a DIY project. I can't find any way to have the pump turn off if heat is not currently needed.