Use Tekmar reset control with MZ boiler?

pch

I am a DIYer. Twenty years ago we purchased a home built in 1898. In the 50s it was turned into 4 apartments, then not much was changed until we started to turn in back into a single-family home.

Prior to our second winter in the house, I removed the ancient, inefficient, 50-year-old beast of a furnace and its ducting, and installed a Monitor MZ 25 (which ran on propane that year. I didn't update the gas service until the following summer). For the past 18 years the MZ has faithfully provided hot water and single high-temp zone heat, supplying a fan coil (SpacePak) in the attic. I am now in the process of installing radiant floor heat on the first floor, old houses can be a bit drafty, which will require a second temperature zone.

Eventually I will need a new boiler, but would like to put that off for now.

OK, large preamble, here comes the question... It's a two-parter.
1. I know that MPI came out with a boiler reset control a couple of years after we installed, but we did not need it because of the single heating zone. The addition of the in-floor heat changes that. I have a Tekmar 422 Reset control. Can that be used in place of the Monitor reset control? How? Specifically, the control wiring: the MPI reset comes with a wiring harness, I have not seen anything in the MZ manual related to connecting a reset. Maybe my manual is too old?
2. Since, at some point, I will need to replace the MZ, I would like to set up the system so that I can swap in the new boiler without making (major) changes.

Thanks for any help.

Ironman

I’m not familiar with that particular boiler, but any control strategy MUST have a matching piping strategy.

We frequency use injection mixing with a Tekmar 356 when two separate SWTs are required. And that will generally work with any type of boiler. I think that the 422 functions similarly. You can also use a smart mixing valve, but again, the piping will have to be made to match the controls.

hot_rod

It was, is a basic on off boiler, one of the very first condenser, not much control logic. A MZ still operating has to be a very rare case

Your next boiler may come with all the control functions, so might not be a good investment to buy a stand alone tekmar?

If you need two temperatures a 3 way valve would be the least expensive option, requiring some piping changes.

pch

I gather from the comments that the MZ does not respond to reset commands? I am a bit confused. What then does the MPI 9110 MZ OUTDOOR RESET CONTROL do?

As for piping, I believe I have a reasonable plan for that. I will install a 30g Boiler Buddy to provide hydraulic separation and some mass to help limit short-cycling. I also will install a 3-way valve with a circulator for the in-floor zone. I was hoping that I could get a lower boiler temp when only the in-floor calls for heat and therefor a bit more efficiency.

Thanks for the comments!

hot_rod

Sounds like you have the optional module. Which, to me, looks suspiciously like a tekmar component

Are you piped primary secondary? I think you need that to get a two temperature system.

Know when you direct pipe the boiler needs 3.5- 4 gpm minimum. So a small zone may not be workable without primary secondary.

The manual has some suggested multi temperature piping options.

Alan (California Radiant) Forbes

Surprisingly, we have 3, maybe 4 still going; parts are still available. They were all installed in 2000. If I had one, I’d be replacing it next summer. 

High temperature systems lasted longer as the condensate from radiant systems eventually compromised the HX. 

Don’t throw a lot of money for ODR on your new radiant. Maybe just a 3-way mixing valve. And you may have to tie it into an existing zone to keep the flow rate high enough to keep the boiler happy.