A standard run of the mill sequencer would work but mounting it would be a hassle in that Rheem unit. Seeing how they want an estimate for replacement and heat is not needed it is fine to just disable the heat strips for the meantime.
Giving em an option to replace is good but honestly if it's just a, sequencer and it's not leaking and pressures are good I would just order the sequencer and install it fur them and also check the ductwork and make sure there are enough supplies and returns and if not get stuff like that corected first as the infostructure is important first so that when it's really time to put a new system in the install can go faster because you addressed the other issues first like for example were the condensate lines done corectly or drain lines and charges remember the older systems hold up more VS new systems and are easier to work on. But obiviosely if it's an old r 22 unit and it's leaking to the point internally where its not worth it to repair it replace it but if the pressures are okay and it's just a, sequencer and no other issues like things I mentioned above like maybe In adaquite ductwork then I as a consumer would be hesitant to just say go ahead and replace right away. But that's just me. But at least give them something to think about for when they are ready for a replacement. Anyway take care.
