[JohnnieSqueeze]

Just finished my first hydronic heating system. I did it in my own house before I venture out to other projects. The problem I am having is the Tagaki water heater I used keeps going to standbye. In order to get it to fire I need to close and then rapidly open any valve in the system. It seems like its not getting enough pressure differential from hot to cold. It is a closed loop system. I am using two Grundfos pumps on one zone. One pump moves water through the pex pipes the other is a recirculator.

Any ideas?


Sent from my iPhone using Tapatalk

 

[dhal22]

Thinking....

 

[JohnnieSqueeze]

According to tagaki the unit activates at a flow of .5gpm and deactivates when it drops to .4gpm. When it does operate it delivers consistent 120 degree water and the flow rate with pumps on is 2.2 GPM. Gas is 1” reduced to 3/4” 5 ft from inlet and it is the first appliance after the meter. No obstructions in 3” venting.


Sent from my iPhone using Tapatalk

 

[Venomthirst]

Combi-boiler or just on demand water heater

 

[JohnnieSqueeze]

Combi-boiler or just on demand water heater

on demand water heater according to Tagaki its rated for residential hydronic


Sent from my iPhone using Tapatalk

 

[ken53]

What temperature is your high limit set to.
Do you have zone valves that are reducing the flow.
Are you getting error codes.
With a system like you speak about, you may need a three way valve to maintain the flow if you heating modulates temperature.

 

[JohnnieSqueeze]

What temperature is your high limit set to.
Do you have zone valves that are reducing the flow.
Are you getting error codes.
With a system like you speak about, you may need a three way valve to maintain the flow if you heating modulates temperature.

The water heater is set at 120. Im not sure what the high limit setting is. It is cycling on and off now. Seems to be running more consistently but not constantly.

My return temp is 105.

I have 3 loops each 300 ft. And I used aluminum plates throught.

The system is floor joist retrofit. I do not have reflective foil in place. I apparently just realized that is necessary this AM.

Grundfos circulators set on high speed.

Thank You for your help. I am going to post a picture of the setup.


Sent from my iPhone using Tapatalk

 

[JohnnieSqueeze]

Update:

Got ahold of Tagaki. Depending upon flow and temp setting the unit auto shuts off. In my case it is when income temp is in excess of 112 degrees. I adjusted the temperature control on the unit to over ride the factory 120 up to 140. This is turn will not shut the unit off until water reaches 132 on the return side.

Also adding double foil bubble insulation.

Much warmer!


Sent from my iPhone using Tapatalk

 

[ken53]

Update:

Got ahold of Tagaki. Depending upon flow and temp setting the unit auto shuts off. In my case it is when income temp is in excess of 112 degrees. I adjusted the temperature control on the unit to over ride the factory 120 up to 140. This is turn will not shut the unit off until water reaches 132 on the return side.

Also adding double foil bubble insulation.

Much warmer!


Sent from my iPhone using Tapatalk

Remember the floor finishes like carpet insulate the floor so it takes more heat in your radiant.:wink:

 

[JohnnieSqueeze]

I have hardwood throughout


Sent from my iPhone using Tapatalk

 

[Venomthirst]

There would definitely be dip switches inside unit to change from 120-130 domestic to a 180 limit on a hydronic system.. awesome thanks for the post and keeping us informed

 

[ShtRnsdownhill]

I have hardwood throughout


Sent from my iPhone using Tapatalk

hard wood temp should be under 90 degrees or you risk warping the wood...





Q. Are there any design limitations you need to be aware of?A. Radiant heat is very efficient but does have some limitations. When ceilings exceed 10’ high, the amount of cubic air that needs to be heated can create problems for a hardwood floor. Rooms with high ceilings can create a situation where the floors can become too warm due to the high volume of space to be heated. Rooms with high ceilings may require radiant heat to be installed in the ceilings and ceiling fans mounted to circulate the air.NOTE: All systems should have a fail-safe to ensure that the surface of the floor never exceeds the recommended surface temperature of 85º

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=12&cad=rja&uact=8&ved=2ahUKEwin6I_XoOvlAhVRJKwKHSIYB7IQFjALegQIABAC&url=https%3A%2F%2Fhallmarkfloors.com%2Fpdfs%2FRadiant-Heat-Guide.pdf&usg=AOvVaw13mBnb4sCEHJVJ9Lh4zju0

 

[JohnnieSqueeze]

The system is operating as it should. It is set at 72 and that seems to be the limit to how high it will go which is more than fine. Next phase is adding more lines and duffuser plates since I only installed one run of 1/2” with plates between each bay. I think it would heat up faster if i doubled the amount of pex and plates. Does that make sense?


Sent from my iPhone using Tapatalk

 

[Venomthirst]

The system is operating as it should. It is set at 72 and that seems to be the limit to how high it will go which is more than fine. Next phase is adding more lines and duffuser plates since I only installed one run of 1/2” with plates between each bay. I think it would heat up faster if i doubled the amount of pex and plates. Does that make sense?


Sent from my iPhone using Tapatalk

Yes and increase efficiency... mod con boilers work best with low return temps and best way to do that is large emitters think infloor poured the entire floor is the heat emitter

 

[Toli]

The system is operating as it should. It is set at 72 and that seems to be the limit to how high it will go which is more than fine. Next phase is adding more lines and duffuser plates since I only installed one run of 1/2” with plates between each bay. I think it would heat up faster if i doubled the amount of pex and plates. Does that make sense?


Sent from my iPhone using Tapatalk

But if the tagaki is a plain Jane tankless it may not give you the flow needed to double the amount tubing. Do your homework before you go to the trouble of adding a bunch of tubing.


Sent from my iPhone using Tapatalk

 

[JohnnieSqueeze]

are you referring to the max flow rating of the machine?

I figured flow was based on speed of grundfos pumps


Sent from my iPhone using Tapatalk

 

[ShtRnsdownhill]

The system is operating as it should. It is set at 72 and that seems to be the limit to how high it will go which is more than fine. Next phase is adding more lines and duffuser plates since I only installed one run of 1/2” with plates between each bay. I think it would heat up faster if i doubled the amount of pex and plates. Does that make sense?


Sent from my iPhone using Tapatalk

how hot is the water going through the pex?

 

[JohnnieSqueeze]

how hot is the water going through the pex?

140


Sent from my iPhone using Tapatalk

 

[Venomthirst]

You should take pictures of your setup so we can see how you got it configured