Hydro air systems controls.?

clammy

I,m not the biggest fan of it especially w air handlers and coils mounted in attics or knee walls but aside from that . What would you use to control or modulate air temp meaning a air sensor 3 way valve tied into a taco hvac relay throw in a freeze stat . Haven’t really looked to deeply into getting a real control on the air temp . Usually when I have encountered them it was in older commercial building and they all used sensor and 3 way valves w globe valves on the by pass they where pretty cool and work well . Am I asking to much or looking to deeply being usually I see glycol zone valves maybe a pump but no checks and of course never any freeze stats . But in thinking if you don’t have the checks you migrate so u don’t need a freeze stat .i also realize that I could use a mod con and fiddle w the outdoor reset to get it right but if your looking at 5 or 6 ah units I rather have some thing that would give me a constant air temp at design day that I could tie a freeze stat to drive open and enable the boiler . So what’s thoughts and who’s valves and controls belimo Honeywell who else is there out there and especially for small applications ranging from 100 to 40 mbtu thanks peace and good luck clammy

SuperTech

I really like the freeze stat idea, it makes too much sense and would require additional parts and labour, no wonder I've never seen anything like it.

clammy

On commercial stuff w outside air and reheat coils always. On the very few residential hydros that I redid I always added a freeze stat it cheap insurance cap tube type and usually a ranco etc for a aquastat for the fan . But I would say most of the residential hydro is terrible but that’s ok cause they it usually matches the rest of the system and what drove the choice . Not that it’s all bad there’s sometimes some that are good and not bubble wrapped but that’s like finding pots of gold and white rhinos in Newark peace and good luck clammy