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We have quit a few protocols with electronic controls they are very reliable. The short cycling normally comes from being oversized. They are not too bad to work on if you can get around them, all the panels come off.

I've only seen one digital scroll down here, on a Kyser-Warren rack. But the controller for it was defective at startup so I never got to see it in action. It will be months before they get a new controller here. I can't wait to get back to the states and civilization! (oh, I forgot. I changed my location on this site to Omaha but I've still got another 10 days to go here in the Caribbean.)

Originally Posted by Oasis Services

makes no sense

What are you talking about???

makes no sense

Then pretty much all you can do is change your sensitivity number to lengthen the compressor cycles.

Originally Posted by man from trane

^ The 4K is now obsolete. Maybe a good time to upgrade to E2. As far as improving control, it's best to have a good range of sizes, such as a small 5 HP compressor, a 10, and several larger ones so that there can always be a combination of pumps running that come close to matching your load. I also find it helpful to stagger defrosts so that you don't have a bunch of cases with no load all at the same time.

Finally, you might consider using SORIT valves instead of suction stops. That way the case is always "on" except in defrost. It evens out the load considerably. I've also had issues with floodback after defrost with the suction stops. Not sure why.

Thanks for the comment!

Our customer that uses Comtrol has chosen to use Danfoss when an overlay is needed. I was hoping they would choose E2.

However, another one of our customers using protocol is using E2. But all systems are suction stop like I mentioned. This comes down from corporate engineering. Nothing I can do about that, they will not allow us to go in and use SORIT. I agree with you, that would make a big difference. To this customer, if it won't save energy, and a lot of it, they won't do it. They use this logic on being resistant to digital scroll.

As far as compressor sizes, I am lucky if the lead compressor is smaller. Most times they are all the same.

With all that, I am having to try to come to a adequate solution with what the customer has given me to work with. Double

^ The 4K is now obsolete. Maybe a good time to upgrade to E2. As far as improving control, it's best to have a good range of sizes, such as a small 5 HP compressor, a 10, and several larger ones so that there can always be a combination of pumps running that come close to matching your load. I also find it helpful to stagger defrosts so that you don't have a bunch of cases with no load all at the same time.

Finally, you might consider using SORIT valves instead of suction stops. That way the case is always "on" except in defrost. It evens out the load considerably. I've also had issues with floodback after defrost with the suction stops. Not sure why.

Originally Posted by MikeySq

do you mean there's protocols with braze in compressors? that's dumb

Got one out there now with 2 suction groups, the #1 comp on the MT side is way too much for low load situation and bangs on and off like crazy, It runs all the time now so the problem is not really fixed, but the suction pressure is a bit lower than it's design

Mike

I have many of these with the same low load issue. Would you elaborate on what you have done to shorten the cycles and smooth out the suction? I would appriciate any successes that any of you have had on this issue.

We have a lot of customers installing protocols with the fixtures all being controlled by suction stop. The load varies greatly all the time and the suction and compressor cycles are all over the road. I have been raising the suction target and insuring that all the fixtures are set at spec for longer system run times and to reduce the suction stop cycles. I have also been playing with the suction setpoint differential, etc (Enhanced suction).
Some success but still looking for input from anyone.

I also have many that are using Comtrol. This is proving to be even more of a challenge as the 4k/4k2 is not as flexible as the E2

I thought if installing a digital scroll but the customer is opposed to using them..... UGH!

I have been using this system for a while. If the system is installed correctly the system will save money over normal system, it uses less freon than most units. It cost less to operate. We use them in Aldi and they love the systems

I'm confused now... haha I've only seen scroll compressors with braze ends with no valves or with roto-lock connected service valves. Just curious what would those standard valves be like??

Originally Posted by MikeySq

so what do they use ball valves for isolation?

The only one I've worked on had standard service valves at each compressor.

so what do they use ball valves for isolation?

Originally Posted by MikeySq

i'd be surprised if you could order them without, that would be just weird!

For some reason you can. It only saves about 40 bucks, which in my opinion is nothing compared to the trouble of buying them separately and brazing them in!

Originally Posted by man from trane

I should have clarified...the customer ordered the compressors. I hope they ordered them with Rotolocks.

i'd be surprised if you could order them without, that would be just weird!

I also like protocols. I think it's a neat idea and the ones I have worked on, have given me little trouble. I mean they break like anything else. Add you fix it and your on down the road.

I'd like to see more of these out there in smaller stores. C Stores, restaurants.

Originally Posted by MikeySq

do you mean there's protocols with braze in compressors? that's dumb

Got one out there now with 2 suction groups, the #1 comp on the MT side is way too much for low load situation and bangs on and off like crazy, It runs all the time now so the problem is not really fixed, but the suction pressure is a bit lower than it's design

Mike

I should have clarified...the customer ordered the compressors. I hope they ordered them with Rotolocks.

Originally Posted by man from trane

I hope the new ones have Rotolocks!

do you mean there's protocols with braze in compressors? that's dumb

Got one out there now with 2 suction groups, the #1 comp on the MT side is way too much for low load situation and bangs on and off like crazy, It runs all the time now so the problem is not really fixed, but the suction pressure is a bit lower than it's design

Mike

Originally Posted by K_Neil

Just started service work on a (approx.) 8 yr. old Hussman Protocol today for the first time. It runs 2 30 ft. cooler displays & 2 cooler walk ins. 4 compressors. 1 display was froze up #1 compressor was an ice block #2 compressor was 1/2 an ice block. Unit alarm light was on. Store owner was watching pretty close and asking a 1000 questions that I couldn't find the answer to untill he gave me some room. U guys bin there dun that. there's a hand held programmer that the owner had hooked up before I could even blink. I have some homework to do and have to figger out the quickest way. Got lucky today and hit the rite buttons. Actually programming everything hasn't ever bin finished by my quick look. The service tech that looked after it before is no longer easily available so I'm under some pressure to figger it all out. Any hints on programming would sure be appreciated. The manuals are there but actual logic sometimes isn't.

I was there a few weeks ago (learning Protocol, not that store ) If yours has CPC and your compressors are short cycling the first thing you will want to do is get the TR (throttling range) above the factory default of 30. I had to go to 60 with an integral of 1.5 to get it steady. (less "P", more "I", no "D") These units are shipped with the minimum programming to get it running and then a tech like yourself is supposed to go in and finish up. Mine short cycled and tore up 3 compressors in 2 years and ran with other problems because no one ever commissioned it.

They're a great system as far as I'm concerned. I'm going to change out some comps on another one in a couple weeks. I hope the new ones have Rotolocks!

Just started service work on a (approx.) 8 yr. old Hussman Protocol today for the first time. It runs 2 30 ft. cooler displays & 2 cooler walk ins. 4 compressors. 1 display was froze up #1 compressor was an ice block #2 compressor was 1/2 an ice block. Unit alarm light was on. Store owner was watching pretty close and asking a 1000 questions that I couldn't find the answer to untill he gave me some room. U guys bin there dun that. there's a hand held programmer that the owner had hooked up before I could even blink. I have some homework to do and have to figger out the quickest way. Got lucky today and hit the rite buttons. Actually programming everything hasn't ever bin finished by my quick look. The service tech that looked after it before is no longer easily available so I'm under some pressure to figger it all out. Any hints on programming would sure be appreciated. The manuals are there but actual logic sometimes isn't.

You start working inside of one, your humor won't be so good.