Troubleshooting Tarm temps.

Something seems amiss.

If the Termovar is functioning properly, the return water line (into the boiler) shouldn't ever stay below 120 except maybe for a white while when the boiler is starting from cold. It's the Termovar's job to adjust the blend so that the boiler can stay at higher temps and then only gradually begin to send heat to storage once the boiler is putting out plenty of heat.

Other factor could be: what are you using for gauges on the boiler in/ out lines? Are they in wells? If not, are they well-bonded and insulated?

Thats the same basic behavior I see with my Tarm 40. I think you are correct, the termovar is recirculating the hot water from the boiler to maintain about 140 - 150 at the boiler inlet. I assume your 120 degree measurement is at the inlet to the termovar from storage, not at the boiler inlet. If you have approx 20 degree rise in water temperature going through your boiler and start with an inlet temperature of 140, that would put the outlet at about 160. If you want a higher outlet temperature, lower the flow rate from storage to the boiler, however this will affect the high temperature operation (unless you increase the flow rate as the temperature of the water coming from storage goes up).

what brand temp gauge? I have two watts and the pressure is wrong on one, and I'm not sure if the temps right on either. The one on the supply is allways 10 F lower than the boiler controller and the one on the return
run 130 when the water is cold and should be 140 F . I'm wondering if they are both off 10 degres. the pressure is way off on the one.

Do you have a partially closed valve in the bypass line to the termovar? Unless there is something I don't understand, the only way you can have 180 on the boiler outlet and inlet is if most of the flow is still going through the bypass on the termovar. By the time the water coming into the termovar from storage is up to 160, the termovar should be fully open between the port coming from storage and the port going to the Tarm. However, the termovar does not close off the bypass line as this port opens. Is this a new installation or was the setup working ok previously? Perhaps a picture or diagram of your piping at the boiler would help with troubleshooting.

Mine does the same. I guessing that more water circulates toward back of boiler and the sensors that read higher are located towards the boiler front.
My tanks also climb in stages.

jimdeq - give us a piping diagram, showing all valves, etc. I have an idea but it would be most helpful to see what you have in place first.

What size circulator are you running on your 60 ?

jimdeq, tell us what kind of valve you have on the bypass and how far closed you have it. My close boiler piping is all 1 1/4" but I made the bypass 1" intentionally. Also, I keep the valve (full port) half closed. It seems to work fine in my case although I wonder if I'm using the proper valve.

The bypass I'm refering to is from the output of the boiler to one of the Termovar ports. Looks like the Tarm diagrams refer to this valve on the bypass as a balancing valve and also recommend to start with it half closed.
/url=http://www.woodboilers.com/admin/uploads/public/WoodBoilerPlumbingSchematic1110Web(1).pdf/url page 12
Tarm doesn't specify on those diagrams but this pipe is the one I intentionally made smaller (1" instead of 1 1/4") to help force more water through the system.
FWIW, I have a EKO 40 with a Danfoss (not Termovar) but everthing appears to work the same.

I needed to up grade to a 26-99 that seems to be a good choice for the 60. I do get some idling when the storage gets up to 180 but this would be expected. Fire should be dieing out about then too.
Tremovar, When I start a burn cycle my return water, 130 range, is cold enough that I just run with Tremovar bypass wide open. Closing it down only drops boiler return temps during start up so I just leave it wide open.
Any thoughts on that ?

Is you Tremovar stamped 72C ? That gives 160F protection. I do know that my start up return 130 from storage mixes to about 148 boiler inlet. I'm not exactly sure what the 160 means but I would guess at 160 it would open fully, closing off continued mixing. This would explain how storage rises in steps.
I'm guessing at this, if some one has facts to share on the operation of a 72C Tremovar, that would be great.

72C = 161.6F. My Danfoss is just 140F. I wonder if the Tarm Sales Guy can comment on this. 161.6F seems like overkill for boiler protection. Hopefully, someone with knowledge of the Termovar & Danfoss valve operation can comment.

I sprayed some select pipes with flat black paint and got out my IR gun. I wasn't able to log complete fire. I had to go out for a couple of hours but I did find a couple of things.
1) My boiler supply (hot out) is much closer to boiler temp ( measured at front of boiler ) than my digital thermostats were leading me to believe.
2) Having my Tremovar fully open was continue to allow mixing with return water temps of 165. Post mixing into boiler was at 175. So the Tremovar doesn't completely close on temp rise. I did close Tremovar some which lowered the post mix water temp and took some heat out of the boiler itself. I will look at the Tremovar during start up tomorrow.

Looking at my danfoss i saw that the thermostat was designed to open after the bybass water reached 140 but there is NO closing of the bypass port so it is always returning a portion of the boiler output back to the boiler return. Always mixing after the boiler is over 140. closing down the ball valve is the only way to reduce or stop the bypass water flow and mixing ( for the danfoss at least )

I've said it before. Nothing causes more questions than the termovar/danfoss thermostatic mixing valves.
A sticky is in order on the function, installation, and maintenance of these gizmos.

The termovar works the same way as the Danfoss. There is no shut off of the bypass flow ever. The termovar element is set up to throttle down the flow coming from storage and mix this with bypass flow taken from the boiler outlet to keep the boiler inlet temperatures above the set point. The colder the water is coming from storage, the more the termovar closes off this port. In my opinion, the inability to close off the bypass port is a weakness in the termovar design, it would be really nice to completely shut off the bypass flow once the water coming from storage is above 140 or so.

If you close the balancing valve too far you will have problems when the storage is cold - I did this once and got operation like the OP with low (~120 or so) storage temps. With the balancing valve closed too far there is not enough flow through the bypass to mix with the cold water coming in from storage. The termovar will decrease the incoming flow from storage until the boiler inlet temperatures are above the termovar set point. If the bypass flow rate is low, the termovar will squeeze down the incoming storage flow resulting in very little flow out of the boiler.

In my case, I had reset my balancing valve when the storage was hot and choked the bypass flow down too far to try and keep the boiler from idling. Once the storage cooled off and I re-fired the boiler it would go to the temperature limit and idle even with storage temperatures of 120. Once I opened the balancing valve a bit everything started working "normal".

I still get idling of my boiler when I have a good fire going and the storage temperatures are 160 -170 on the bottom of the tank. The top of the tank is at 185 to 190 when this happens. I assume in this case there is too much bypass flow as the termovar does not close down the bypass port.

jimdeq & robc, I suspect you may have more idling that I do since you have larger boilers. I assume we have the same size termovar - mine is 1 1/4 - I'll have to check the temperature rating as is sounds like my boiler inlet runs cooler than yours. With the storage cold, I get 145 - 150 at the boiler inlet. I wonder if the termovar restriction is more noticeable with a larger boiler. I have a Taco 007 between my boiler and storage, the storage piping is about 15 feet of 1 1/4 copper. You might try running your pump on high speed to see if the additional flow makes any difference

I do run my pump on high. The 1.25 Tremovar is supposed to be OK with these boilers. When I needed to up-size boiler pump I checked with Tarm NH and got their OK on both items. If I recall the Tremovar and Danfos are rated on their CV value / rating for an application. Can't remember what the CV value defination is.
I do believe there is a lower rated Tremovar available also.