Recent content by u3b3rg33k

keep in mind even a TEFC motor is only rated for so many starts/hr. the only way to get "unlimited" is typically TEBC or controlled acceleration (drive/soft starter). but even the soft starters are rated for something like 5/hr. so basically you need a lift VFD and an appropriate motor if you...

I have a similar issue, but it's because someone decided to put about 150' of pipe in my house that runs around their remodel instead of a more traditional layout - about half of which is still galvanized. if you're at the water heater, however, the outlet is up to temp in <5s. I also typically...

it's not gas furnace slow. pretty much it slams the gas on max then dials back once it hits temp. 199k BTU is a lotta fire. DHW tankless units are typically way more aggressive on startup than a CH/boiler. no one cares if it takes 5 seconds to light off a boiler. EVERYONE cares if it takes...

a friendly reminder - motor dataplates list RATED power/current. if your LOAD doesn't require it, it won't pull it. lift with a car on it uses more amps than a lift without a car on it.

this is not at all how my rinnai works. basically zero cold water comes out the "hot" port. and yes it's in "eco" mode. i mean it does all those things just nearly instantaneously. it even stays spun up for a bit for faster relight after a draw.

idk how long it really takes my washer can slam the hot solenoid on/off/on/off/on/off all it likes and there's no cold water sammich.

I don't have this issue OR an internal buffer tank. my only issue is old galvanized hot water lines that are waiting for replacement.

heh I asked AI how to keep a motor under it's rated limit, and it told me to use the drive's protection current limit feature, and to NOT use the PI logic with amperage as the input value. I asked it specifically to tell me how to use the PI logic. lol!

if the chrome ain't chippin', you ain't hittin'

my fancy puller doesn't seem to have acme threads:

there's more than a handful of models meant for small motors that take in 120V. https://www.invertekdrives.com/variable-frequency-drives/optidrive-e3/drive-configurator if we do the math we run out of amps pretty fast on 120V input power. 5.8A*1.73*2=20.068 A so I assume that's why they stop...

120V input VFDs typically have voltage doublers. kinda like old computer power supplies had that 120/220v toggle switch. same thing. fun fact, you can run a 400v class VFD on 200v class power with... a DIY voltage doubler feeding the DC bus! precharge resistor recommended. as always, try not...

I don't think size matters as much as what the application specifies. I happen to have a rinnai i120cn, and i've got it set up for simultaneous DHW & CH (not the default), and the only downside is while you're drawing hot water, you get 140F CH water at whatever rate it decides it can give you...

there are operational compromises with a combi for sure. by default many of them operate in 'hot water priority' so NO CH during DHW.