I will try to explain this the best I can, with my primary/secondary setup I have oil and wood boilers both plumbed into a primary loop that is supplying a low temp radiant zone and high temp baseboard zone. Currently my primary pump runs continuously(controlled by me by a regular switch). To make a long story short (keep in mind I am a plumber by trade but fairly knowledgeable in the 120/240v and somewhat in the low voltage range of electrical work) I want two aquastats to control one primary pump. I either have the TT (low voltage) contacts to work with or the C1 (line voltage) aquastat relay to work with. In my mind a relay similar to the ly2 (one contact coil operating a DPDT switch[spst would work I think if choices are limited]) does such a thing exist as a relay with 2 contact coils (either 24vac or 110vac) that would pull the same set of contacts powering the primary pump? Any other suggestions that I am totally overlooking? Looking for an answer kind of on the cheap side of things! Hopefully this is somewhat clear, at least to an electrician or low voltage controls guy =) Thanks! Just re-read this and want to add this, both aquastats C1 contacts control their own pumps injecting water into the primary loop, I want to piggy back of the c1 (or TT if it makes things simplier) contact without back feeding the pump controlled by the second aquastat.