Delta T Taco Circ not holding 20 deg diff.

Rich Davis_2

Starting about 3 weeks ago I noticed that the inlet and outlet temp is of my TT PS60 is not holding the 20 deg diff. Sometimes it's a couple deg one way or the other, this evening I noticed it was 10 deg off at outlet temp of 160 it was reading 130 return, any suggestions? Thanks loads

Rich_49

What type of heating system . Radiant , baseboard , radiators ?
What were your conditions like 3 weeks ago as opposed to today . Are the sensors insulated , in wells ? Where is the circ in relation to the boiler , is it remote or right at the unit ?

Who designed and spec'd what was used ?

Rich Davis_2

Thanks for the reply. I designed and installed my heating system. In 2010 I attended Taco's class "The Complete Boiler Room" with John Barba as instructor and Triangle Tube's class on their boiler. My system uses a TT PS 60 and is piped 1 zone and 4 loops, pumping away. It has worked great fine for the last 4 years. The thermistor for the supply is located inside the boiler cabinet strapped to the pipe and the one for the return isolated outside the boiler strapped to the pipe and is covered with insulation. The circ. is located next to the boiler on the same board. The weather was pretty warm around Christmas and then got cold, in the teens at night, that's about the time it started messing up. Sometimes it's only a couple deg. off and others times it might be as much as 10 deg. off. Any thoughts?

Gordy

Bad thermistors maybe. Also maybe the thermistor in the boiler cabinet influenced by ambient temp inside cabinet. Try moving it outside the cabinet if possible. all though if it has been in place since 2010 that is not likely the culprit.

Ironman

What about boiler output?

We're assuming the issue lies with the circ or its sensors, but if the boiler is down-firing because of an issue, then the delta T would be widened as the load increased.

Jean-David Beyer

I do not have a delta t circulator, but since my boiler has outdoor reset, it can drop the supply temperature to 80f if it is over 50F outside. If it did that, my hypothetical delta t circulator would have a tough time maintaining 20F delta t into my slab.

Gordy

I'm under the impression that this has been in place, and worked since original install in 2010?