Upgrade to Tekmar

Allan_6

Can someone make a recommendation for a combination of controllers for upgrading an existing system?
It is a 7000 sq ft. home built in 1950 with mostly radiant ceilings. 18 yr old mixing valves (on TSA controllers), 2 of the 3 are faulty and we are putting a proposal together with some piping upgrades and replacement controls. The owner is looking for constant circulation as much as possible, and understands the concepts of reset and radiant. The boiler and pumps are remaining.
Want to reset the boiler temp, have 4 mix temperatures, and there are 8 pumps. Local vendor has been little help.
He suggested either a #360 for each temperature, or the newer TN4 set up, consisting of I'm not sure what. Problem wiith TN4 is you need 4 wire to thermostats which are only 2 wire, and may be to much work to change. I've looked at the various controllers on the web, but have no first hand knowledge of them. I'm wondering about combining a #369 (or 2)zone unit with a 374 universal and one other (?) to acheive a full system. I may also leave in service the existing pump relays. My understanding is you won't get as full fuction of parallel shift with the older styles as you would with the TN4 system.

GW

multiple

Allan, I feel your pain. I inquired with Mike at Tekmar (very sharp dude) and he confirmed that yes indeed you would need seperate controls which gets very costly. Please email me someday when you have it all fiqured out, I'd love to know.

Gary

gary@wilsonph.com

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Weezbo

have you taken a look at the TACO LOAD MATCH program

Dan recently posted a thread for the new products catalogue...

the program is relatively straight forward,you can do your hydronic lay out ,check all the numbers, apply various control strategies ,erase them all,.... Watts radiant has a program that you can import more information that is standardised into the program,...and the LOAD MATCH program allows you to import various pieces from other sources,and run the various sub systems loads and check what the outcome will be.... just a thought.

now that i have mentioned this.....i wonder if they have included the RBM ,the TACO X Block, The I series Setpoint and I series R (with outdoor reset) 4 way mixing valves ,three way and two way set point....i think maybe i should check if there is an update to the program...on the site...hmmm...*~/:)

Unknown

Why four mixed temps? You can do a lot with flow control with ceilings to approximate different average temps in the ceilings.

Or, you could mix a master temp and use setpoint tempering valves to limit temperatures to select zones.. or, mix a master temp and look at TRV-type devices like Oventrop's "Uniboxes" to handle constant circ to other zones (haven't used them yet myself, but I would look hard at them if I were looking at 4 mix temps).

Maybe a 363/369 setup with 062 RTUs (two wire I believe); the system will find the zone that needs the most heat, constant circ that one (until another zone becomes the "lead"), and use PI/PID logic to cycle the remaining zones with the minimum water temp the system (lead zone) needs. This is *most likely* the best way to "approximate" constant circ in your multiple zone system, if the water temps are not TOO far apart. Full indoor/outdoor feedback and boiler control, DHW integration, high temp capability as well.

Otherwise the 360 for each temp will give you 4 constant circulation circuits, so that's not a crazy recommendation.. 4 mix temps is a little much IMHO but I don't know what else is in the system either...

Tom Kane

tekmar upgrade..............

Do you know the 4 diferent temps...........

Allan_6

Thanks all for replies,
The system now has 3 temps (all reset)as designed in 1987, when a boiler and other upgrades to the 1950 house took place. A small wing with conventional radiation at 180 @ ODT on one pump; remainder of house ceilings at 130 @ ODT on 6 pumps; and perimeter of all floors (2 or 3 passes typ.) at 105 or 110 on 1 pump. We were going to subdivide one side of house ceilings with a 4th temp (2 of the 6 pumps)to give owner flexibility to keep it cooler but with continuous circulation. He wants to minimize lag and expansion concerns of cycling pump on and off. We thought about balancing down the flow (manually) but seems not good for times when they want to warm up the cooler area. We are only working within the mechanical room, not altering the distribution other than the 4th mixing valve.
I'm trying to reason or compare the expense of TN4 system and running new 4 wire to tstats against a collection of older style units. By the way, we started with just wanting to replace the bad mixing valves, but no controls contractor would offer valves to work with the existing controllers, only matched pairs, so we decided to explore the Tekmars.
Allan