NFB 200 on snowmelt system

ahelwig

I installed a snow melt system heated by an Navian fire tube boiler. I do not have the outdoor sensor hooked up. I do NOT have any automatic freeze or water sensors on slab to tell system to turn on (they are expensive and often turn systems on too late (after the snow starts falling instead of before)). It is simple, I have a couple pumps that pump water to my loops plugged into wifi plugs that I turn on and off from my phone. An hour or so before it starts snowing I tell my phone to turn on plug that turns on a pump that then triggers the flow switch in the boiler to fire away. Then when its actually starts snowing my slab is warm. This all works well. This is my first winter using it and so far haven't had to pull out a shovel at all. To make this work I have a jumper in my boiler where the two thermostat wires would usually go. SO the boiler always thinks the thermostat is aways calling for heat. But the boiler really doesn't fire unless I have a zone pump on. Like I said this all really works very well for me.
Here is my problem. Ther is an extra pump that doesn't go to any of my loops in the driveway. I think the plumber called it a "boiler loop". its just a small loop that runs just below the boiler Id say only about 5' of total run. Its my understanding what that was for was in case the boiler was running and any of my pumps stopped working the boiler would automatically kick on this boiler loop pump so water was running through the boiler and it wont burn up. So this is what I noticed. There are times when I am not running any of my snow melt loop pumps. For instance there is probably 8 months a year none of my heating pumps are running because there is no chance of snow. You would think then the boiler would be running during this time. However it does. There must be something in its programming telling it to keep warm internally so it fires up (even though none of my pumps are on) and then so it doesn't over heat it tells the boiler loop to kick on. SO I am wondering if there is some way to get into its programming to tell it NOT to do that internal warming. This way it will only kick on when I turn on a loop pump.
Its not like its running 24/7 when I am not calling for heat but Id say every 15 minutes it turns on for 3-5 minutes. It just seems silly for it to run like that on this system. I could just turn off the boilers but then that take away the convenience of using my phone to turn on and off he system from in bed in the middle of the night. Every time I wanted to turn it off an on I would have to walk out to the detached garage and turn it on manually.
Any Navian experts out there?

GroundUp

It doesn't take a Navien tech to figure out that the controls are simply hacked in. Your wifi plugs should be connected to a relay of some sort (I'm not an electrician) which closes when you activate the control and fires the boiler only at that point. There is absolutely no reason to keep that thing hot 365 days a year instead of only on snow days. It's got 20 winters of run time on it now instead of one. I would not be very happy with the installer, personally.

Paul Formisano

I see at least two ways to fix this.  

First option, put the boiler on the WiFi switch too, not just the pump.  

Second option, use the WiFi switch to close a 120VAC coil relay to close a dry contact across the t-stat that should call for the pump and boiler at the same time.  Remove the permanent jumper across the t-stat. 

 The pump on the boiler ensures enough flow always goes past the boiler when it is on and protects it regardless of the demand of a secondary pump loop.