Several people in this post don't like having the mash vessel up high. "a high mash tun just makes no sense to me." That kind of makes sense to me.
http://morebeer.com/phpBB2/viewtopic.php?t=14486&postdays=0&postorder=asc&start=15
One guy says this.
"I built a 1550, but regret it because I don't want to lift a keg up to the top.
If I can sell it, I'll build a single tier like yours."
Another guy says this.
"I like that setup too, I dont like filling my hlt on a ladder or lifting even that empty keg up that high. The only thing that is holding me back is the price of the pump."
I am thinking of going single tier or maybe 1.5 tier, with the boiling kettle nearly on the floor. I still like the idea of the mash vessel gravity draining into the boiler.
A true single tier system needs 2 pumps. The interesting thing about using two pumps is that it makes a HERMs setup really easy in that one pump can pump HLT water through a CCF and another pump can circulate wort through the other side of it. Not a bad way to heat wort if you ask me.
I might use both my steam masher and the CCF idea. That is overkill, but you can bet that between the two I will always have a way to control my mash temps !
Another thing I read over and over it everyone hates digging the spent grains out of the mash vessel. I really like the idea of having the mash vessel on a tipping mechanism.
The things I don't like about a single tier system is that its about 2 feet longer to store (6' long versus 4' long) and it probably needs a second pump and then the wort is pumped rather than gravity fed into the boiler during sparge. I don't know if I like that.
I wonder if putting a nice big fold up platform on the side of the 1550 design would help. So that its easy and comfortable to look at/work with the mash. It would still be a bit of a pain to get up there all the time.