Troubleshooting & FAQ
Analysis problems
"Analysis server is waking up — free hosting can take up to a minute…" Normal. The backend sleeps when idle; the app wakes it when you open it and before every solve. If it still fails after the wait, check your connection and try again in a minute.
"Model appears unstable or under-constrained" A rigid-body motion (translation or rotation) is unrestrained, or a sub-assembly is disconnected. Add an anchor, check guides restrain both lateral axes somewhere, and run Check Model — it counts restraints and shows the analysis mesh. Watch for accidentally disconnected segments (a node created twice at slightly different coordinates).
"Geometry error: Bend at node N: tangent length … does not fit within adjacent element …" The bend radius is too big for a leg, or you attached a flange/valve directly to the bend/tee node. The message states the minimum pipe spool length — insert it, shorten the radius, or move the component.
"Tee at node N was SKIPPED: it has 2 connected element(s)…" A TEE component needs exactly three connected elements. With fewer/more it is solved as a plain intersection without tee SIFs — fine only if it isn't really a tee (e.g. the branch line lives in another un-imported PCF).
"Nonlinear solver did not fully converge…" / "Support kept alternating…" The friction/gap iteration hit its limits; results are the most-settled state. Usually a support sitting exactly at its friction limit or a gap that opens and closes marginally — review μ and gaps at the named nodes. Reducing an unrealistically high μ often fixes it.
Results look absurd (kilometre deflections, 1e9 stresses) The model is a mechanism the pre-checks couldn't see — usually everything is only supported vertically with nothing lateral. Add a guide or anchor.
Modelling questions
How do I model equipment nozzle movements? Anchor at the nozzle with imposed displacements equal to the equipment's thermal growth.
How do I cap a line end? Route tab → Flange Element → Blind Flange → Route Component. It caps the current node (needs exactly one connected element).
Why did my flange's mass change to 20 kg? It didn't — since v2 the entered mass is always kept. Re-enter it if the model predates that fix.
Why can't I put a support on a bend's curve? Supports go on nodes. Put a node on the adjacent straight pipe (Insert Support Along Element splits it for you). The bend TIP node's restraint is applied at the near tangent point.
One model, two design conditions? Specifications — per-line pressure, temperatures, code and cycles.
Where did my analysis results go after an edit? Any model edit invalidates results (the viewer returns to pre-analysis). Re-run — or use Run All so every case is one click.
Data questions
Is my work saved? Auto-saved to your browser continuously. For real backup: Download .psm or Save to Cloud (Pro). Results are never saved — models are.
Can I move a model between accounts/machines? .psm files or a share link.
My PCF import looks wrong. Read the import summary's warnings/assumptions first — nearly every surprise is listed there (fallback schedules, assumed ratings, unmatched supports, tie-ins to lines you didn't import). The Preview Analysis Mesh shows exactly what will be solved.
Accuracy & responsibility
PipeFEA is under active development and its results are not independently certified. Every report carries the engineering disclaimer: results are for preliminary checking and must be verified by a qualified piping engineer before use in design, fabrication or construction. The Technical Reference documents every method and assumption so you can verify against hand calculations or other software.